[Erlang] Add Erlang server generator (#3758)

* Initial erlang generation

* Recfactor erlang codegen to make a minimal working example

* ft/erlang_codegen Separate handlers by resourse, add minor codegen fixes and refactoring

* Test commit

* ft/erlang_codegen Modify reouting generation

* ft/erlang_codegen Remove parsed request concept. Add minor refactoring and bugfixes

* ft/erlang_codegen Use swagger spec from an internal directory instead of a provided path

* ft/erlang_codegen Add basic response validation

* ft/erlang_codegen Moved all the req validators to a separate file for test needs

* ft/erlang_codegen Add basic param validation

* Add refactoring:
OperationIDs are atoms now
Fix schema validation
Add todo list

* CAPI-23 Add auth context to request handling (#2)

* CAPI-23 Fix routing to support different paths in one handler. Add auth context to request handling. Add an opportunity to pass custom middlewares to the server

* CAPI-31 Add enum validation and some minor fixes (#4)

* CAPI-31 Fix turbo fuck up with additional params (#5)

* Capi 23/fix/basic logging (#6)

* CAPI-23 Add understandable messages in case of bad requests. Add specs to shut up dialyzer and add some minor code refactoring

* CAPI-23 Fix missed bracket in auth module (#7)

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/ErlangServerCodegen.java

@@ -0,0 +1,267 @@
+package io.swagger.codegen.languages;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Multimap;
+import io.swagger.codegen.*;
+import io.swagger.models.*;
+import io.swagger.util.Json;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+import java.io.IOException;
+import java.math.BigDecimal;
+import java.util.*;
+import java.util.Map.Entry;
+import org.apache.commons.lang3.StringUtils;
+
+public class ErlangServerCodegen extends DefaultCodegen implements CodegenConfig {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(ErlangServerCodegen.class);
+
+    protected String apiVersion = "1.0.0";
+    protected String apiPath = "src";
+    protected String packageName = "swagger";
+
+    public ErlangServerCodegen() {
+        super();
+
+        // set the output folder here
+        outputFolder = "generated-code/erlang-server";
+
+        if (additionalProperties.containsKey(CodegenConstants.PACKAGE_NAME)) {
+            setPackageName((String) additionalProperties.get(CodegenConstants.PACKAGE_NAME));
+        } else {
+            additionalProperties.put(CodegenConstants.PACKAGE_NAME, packageName);
+        };
+
+        /**
+         * Models.  You can write model files using the modelTemplateFiles map.
+         * if you want to create one template for file, you can do so here.
+         * for multiple files for model, just put another entry in the `modelTemplateFiles` with
+         * a different extension
+         */
+        modelTemplateFiles.clear();
+
+        /**
+         * Api classes.  You can write classes for each Api file with the apiTemplateFiles map.
+         * as with models, add multiple entries with different extensions for multiple files per
+         * class
+         */
+        apiTemplateFiles.put(
+            "handler.mustache",   // the template to use
+            ".erl");       // the extension for each file to write
+
+        /**
+         * Template Location.  This is the location which templates will be read from.  The generator
+         * will use the resource stream to attempt to read the templates.
+         */
+        embeddedTemplateDir = templateDir = "erlang-server";
+
+        /**
+         * Reserved words.  Override this with reserved words specific to your language
+         */
+        setReservedWordsLowerCase(
+            Arrays.asList(
+                "after","and","andalso","band","begin","bnot","bor","bsl","bsr","bxor","case",
+                "catch","cond","div","end","fun","if","let","not","of","or","orelse","receive",
+                "rem","try","when","xor"
+            )
+       );
+
+        instantiationTypes.clear();
+
+        typeMapping.clear();
+        typeMapping.put("enum", "binary");
+        typeMapping.put("date", "date");
+        typeMapping.put("datetime", "datetime");
+        typeMapping.put("boolean", "boolean");
+        typeMapping.put("string", "binary");
+        typeMapping.put("integer", "integer");
+        typeMapping.put("int", "integer");
+        typeMapping.put("float", "integer");
+        typeMapping.put("long", "integer");
+        typeMapping.put("double", "float");
+        typeMapping.put("array", "list");
+        typeMapping.put("map", "map");
+        typeMapping.put("number", "integer");
+        typeMapping.put("bigdecimal", "float");
+        typeMapping.put("List", "list");
+        typeMapping.put("object", "object");
+        typeMapping.put("file", "file");
+        typeMapping.put("binary", "binary");
+        typeMapping.put("bytearray", "binary");
+        typeMapping.put("byte", "binary");
+        typeMapping.put("uuid", "binary");
+        typeMapping.put("password", "binary");
+
+        cliOptions.clear();
+        cliOptions.add(new CliOption(CodegenConstants.PACKAGE_NAME, "Erlang package name (convention: lowercase).")
+            .defaultValue(this.packageName));
+        /**
+         * Additional Properties.  These values can be passed to the templates and
+         * are available in models, apis, and supporting files
+         */
+        additionalProperties.put("apiVersion", apiVersion);
+        additionalProperties.put("apiPath", apiPath);
+        /**
+         * Supporting Files.  You can write single files for the generator with the
+         * entire object tree available.  If the input file has a suffix of `.mustache
+         * it will be processed by the template engine.  Otherwise, it will be copied
+         */
+        supportingFiles.add(new SupportingFile("rebar.config.mustache","", "rebar.config"));
+        supportingFiles.add(new SupportingFile("app.src.mustache", "", "src" + File.separator + this.packageName + ".app.src"));
+        supportingFiles.add(new SupportingFile("router.mustache", "",  toSourceFilePath("router", "erl")));
+        supportingFiles.add(new SupportingFile("api.mustache", "",  toSourceFilePath("api", "erl")));
+        supportingFiles.add(new SupportingFile("server.mustache", "",  toSourceFilePath("server", "erl")));
+        supportingFiles.add(new SupportingFile("utils.mustache", "",  toSourceFilePath("utils", "erl")));
+        supportingFiles.add(new SupportingFile("auth.mustache", "",  toSourceFilePath("auth", "erl")));
+        supportingFiles.add(new SupportingFile("swagger.mustache", "", toPrivFilePath("swagger", "json")));
+        supportingFiles.add(new SupportingFile("default_logic_handler.mustache", "",  toSourceFilePath("default_logic_handler", "erl")));
+        supportingFiles.add(new SupportingFile("logic_handler.mustache", "",  toSourceFilePath("logic_handler", "erl")));
+        writeOptional(outputFolder, new SupportingFile("README.mustache", "", "README.md"));
+    }
+
+    @Override
+    public String apiPackage() {
+        return apiPath;
+    }
+
+    /**
+     * Configures the type of generator.
+     *
+     * @return the CodegenType for this generator
+     * @see io.swagger.codegen.CodegenType
+     */
+    @Override
+    public CodegenType getTag() {
+        return CodegenType.SERVER;
+    }
+
+    /**
+     * Configures a friendly name for the generator.  This will be used by the generator
+     * to select the library with the -l flag.
+     *
+     * @return the friendly name for the generator
+     */
+    @Override
+    public String getName() {
+        return "erlang-server";
+    }
+
+    /**
+     * Returns human-friendly help for the generator.  Provide the consumer with help
+     * tips, parameters here
+     *
+     * @return A string value for the help message
+     */
+    @Override
+    public String getHelp() {
+        return "Generates an Erlang server library using the swagger-tools project.  By default, " +
+                "it will also generate service classes--which you can disable with the `-Dnoservice` environment variable.";
+    }
+
+    @Override
+    public String toApiName(String name) {
+        if (name.length() == 0) {
+            return this.packageName + "_default_handler";
+        }
+        return this.packageName + "_" + underscore(name) + "_handler";
+    }
+
+    /**
+     * Escapes a reserved word as defined in the `reservedWords` array. Handle escaping
+     * those terms here.  This logic is only called if a variable matches the reseved words
+     *
+     * @return the escaped term
+     */
+    @Override
+    public String escapeReservedWord(String name) {
+        return name + "_";  // add an underscore to the name
+    }
+
+    /**
+     * Location to write api files.  You can use the apiPackage() as defined when the class is
+     * instantiated
+     */
+    @Override
+    public String apiFileFolder() {
+        return outputFolder + File.separator + apiPackage().replace('.', File.separatorChar);
+    }
+
+    @Override
+    public String toModelName(String name) {
+        return camelize(toModelFilename(name));
+    }
+
+    @Override
+    public String toOperationId(String operationId) {
+        // method name cannot use reserved keyword, e.g. return
+        if (isReservedWord(operationId)) {
+            LOGGER.warn(operationId + " (reserved word) cannot be used as method name. Renamed to " + camelize(sanitizeName("call_" + operationId)));
+            operationId = "call_" + operationId;
+        }
+
+        return camelize(operationId);
+    }
+
+    @Override
+    public String toApiFilename(String name) {
+        return toHandlerName(name);
+    }
+
+    @Override
+    public Map<String, Object> postProcessOperations(Map<String, Object> objs) {
+        Map<String, Object> operations = (Map<String, Object>) objs.get("operations");
+        List<CodegenOperation> operationList = (List<CodegenOperation>) operations.get("operation");
+        for (CodegenOperation op : operationList) {
+            if (op.path != null) {
+                op.path = op.path.replaceAll("\\{(.*?)\\}", ":$1");
+            }
+        }
+        return objs;
+    }
+
+    @Override
+    public Map<String, Object> postProcessSupportingFileData(Map<String, Object> objs) {
+        Swagger swagger = (Swagger)objs.get("swagger");
+        if(swagger != null) {
+            try {
+                objs.put("swagger-json", Json.mapper().writeValueAsString(swagger));
+            } catch (JsonProcessingException e) {
+                LOGGER.error(e.getMessage(), e);
+            }
+        }
+        return super.postProcessSupportingFileData(objs);
+    }
+
+    public void setPackageName(String packageName) {
+        this.packageName = packageName;
+    }
+
+    protected String toHandlerName(String name) {
+        return toModuleName(name) + "_handler";
+    }
+
+    protected String toModuleName(String name) {
+        return this.packageName + "_" + underscore(name.replaceAll("-", "_"));
+    }
+
+    protected String toSourceFilePath(String name, String extension) {
+        return "src" + File.separator +  toModuleName(name) + "." + extension;
+    }
+
+    protected String toIncludeFilePath(String name, String extension) {
+        return "include" + File.separator + toModuleName(name) + "." + extension;
+    }
+
+    protected String toPrivFilePath(String name, String extension) {
+        return "priv" + File.separator + name + "." + extension;
+    }
+}

modules/swagger-codegen/src/main/resources/META-INF/services/io.swagger.codegen.CodegenConfig

@@ -51,3 +51,4 @@ io.swagger.codegen.languages.ClojureClientCodegen
 io.swagger.codegen.languages.HaskellServantCodegen
 io.swagger.codegen.languages.LumenServerCodegen
 io.swagger.codegen.languages.GoServerCodegen
+io.swagger.codegen.languages.ErlangServerCodegen

modules/swagger-codegen/src/main/resources/erlang-server/README.mustache

@@ -0,0 +1,12 @@
+# Swagger rest server library for Erlang
+
+## TODO
+- [ ] Write specs for static exported fuctions
+- [ ] Write specs for generated exported fuctions
+- [ ] Add datetime/date validation
+- [ ] Separate gigantic `api` to submodules and refactor the routing
+- [ ] Add tests for the validators
+- [ ] Add integrational test for the whole cycle
+- [ ] Add validations of definitions with inheritance
+- [ ] Add proper response validation (this `list` hack is so weird)
+- [ ] Fix enum validation. It doesn't work correctly when the parans is in qs/header

modules/swagger-codegen/src/main/resources/erlang-server/api.mustache

@@ -0,0 +1,345 @@
+-module({{packageName}}_api).
+
+-export([request_params/1]).
+-export([request_param_info/2]).
+-export([populate_request/3]).
+-export([validate_response/4]).
+
+-type operation_id() :: atom().
+-type request_param() :: atom().
+
+-export_type([operation_id/0]).
+
+-spec request_params(OperationID :: operation_id()) -> [Param :: request_param()].
+{{#apiInfo}}{{#apis}}
+{{#operations}}{{#operation}}
+request_params('{{operationId}}') ->
+    [{{#allParams}}{{^isBodyParam}}
+        '{{baseName}}'{{/isBodyParam}}{{#isBodyParam}}
+        '{{dataType}}'{{/isBodyParam}}{{#hasMore}},{{/hasMore}}{{/allParams}}
+    ];
+{{/operation}}{{/operations}}{{/apis}}{{/apiInfo}}
+request_params(_) ->
+    error(unknown_operation).
+
+-type rule() ::
+    {type, 'binary'} |
+    {type, 'integer'} |
+    {type, 'float'} |
+    {type, 'binary'} |
+    {type, 'boolean'} |
+    {type, 'date'} |
+    {type, 'datetime'} |
+    {enum, [atom()]} |
+    {max, Max :: number()} |
+    {exclusive_max, Max :: number()} |
+    {min, Min :: number()} |
+    {exclusive_min, Min :: number()} |
+    {max_length, MaxLength :: integer()} |
+    {min_length, MaxLength :: integer()} |
+    {pattern, Pattern :: string()} |
+    schema |
+    required |
+    not_required.
+
+-spec request_param_info(OperationID :: operation_id(), Name :: request_param()) -> #{
+    source => qs_val | binding | header | body,
+    rules => [rule()]
+}.
+
+{{#apiInfo}}{{#apis}}
+{{#operations}}{{#operation}}{{#allParams}}
+request_param_info('{{operationId}}', {{^isBodyParam}}'{{baseName}}'{{/isBodyParam}}{{#isBodyParam}}'{{dataType}}'{{/isBodyParam}}) ->
+    #{
+        source => {{#isQueryParam}}qs_val{{/isQueryParam}} {{#isPathParam}}binding{{/isPathParam}} {{#isHeaderParam}}header{{/isHeaderParam}}{{#isBodyParam}}body{{/isBodyParam}},
+        rules => [{{#isString}}
+            {type, 'binary'},{{/isString}}{{#isInteger}}
+            {type, 'integer'},{{/isInteger}}{{#isLong}}
+            {type, 'integer'},{{/isLong}}{{#isFloat}}
+            {type, 'float'},{{/isFloat}}{{#isDouble}}
+            {type, 'float'},{{/isDouble}}{{#isByteArray}}
+            {type, 'binary'},{{/isByteArray}}{{#isBinary}}
+            {type, 'binary'},{{/isBinary}}{{#isBoolean}}
+            {type, 'boolean'},{{/isBoolean}}{{#isDate}}
+            {type, 'date'},{{/isDate}}{{#isDateTime}}
+            {type, 'datetime'},{{/isDateTime}}{{#isEnum}}
+            {enum, [{{#allowableValues}}{{#values}}'{{.}}'{{^-last}}, {{/-last}}{{/values}}{{/allowableValues}}] },{{/isEnum}}{{#maximum}}
+            {max, {{maximum}} }, {{/maximum}}{{#exclusiveMaximum}}
+            {exclusive_max, {{exclusiveMaximum}} },{{/exclusiveMaximum}}{{#minimum}}
+            {min, {{minimum}} },{{/minimum}}{{#exclusiveMinimum}}
+            {exclusive_min, {{exclusiveMinimum}} },{{/exclusiveMinimum}}{{#maxLength}}
+            {max_length, {{maxLength}} },{{/maxLength}}{{#minLength}}
+            {min_length, {{minLength}} },{{/minLength}}{{#pattern}}
+            {pattern, "{{pattern}}" },{{/pattern}}{{#isBodyParam}}
+            schema,{{/isBodyParam}}{{#required}}
+            required{{/required}}{{^required}}
+            not_required{{/required}}
+        ]
+    };
+{{/allParams}}{{/operation}}{{/operations}}{{/apis}}{{/apiInfo}}
+request_param_info(OperationID, Name) ->
+    error({unknown_param, OperationID, Name}).
+
+-spec populate_request(
+    OperationID :: operation_id(),
+    Req :: cowboy_req:req(),
+    ValidatorState :: jesse_state:state()
+) ->
+    {ok, Model :: #{}, Req :: cowboy_req:req()} |
+    {error, Reason :: any(), Req :: cowboy_req:req()}.
+
+populate_request(OperationID, Req, ValidatorState) ->
+    Params = request_params(OperationID),
+    populate_request_params(OperationID, Params, Req, ValidatorState, #{}).
+
+populate_request_params(_, [], Req, _, Model) ->
+    {ok, Model, Req};
+
+populate_request_params(OperationID, [FieldParams | T], Req0, ValidatorState, Model) ->
+    case populate_request_param(OperationID, FieldParams, Req0, ValidatorState) of
+        {ok, K, V, Req} ->
+            populate_request_params(OperationID, T, Req, ValidatorState, maps:put(K, V, Model));
+        Error ->
+            Error
+    end.
+
+populate_request_param(OperationID, Name, Req0, ValidatorState) ->
+    #{rules := Rules, source := Source} = request_param_info(OperationID, Name),
+    {Value, Req} = get_value(Source, Name, Req0),
+    case prepare_param(Rules, Name, Value, ValidatorState) of
+        {ok, Result} -> {ok, Name, Result, Req};
+        {error, Reason} ->
+            {error, Reason, Req}
+    end.
+
+-spec validate_response(
+    OperationID :: operation_id(),
+    Code :: 200..599,
+    Body :: jesse:json_term(),
+    ValidatorState :: jesse_state:state()
+) -> ok | no_return().
+{{#apiInfo}}{{#apis}}
+{{#operations}}{{#operation}}
+{{#responses}}
+validate_response('{{operationId}}', {{code}}, Body, ValidatorState) ->
+    validate_response_body('{{dataType}}', '{{baseType}}', Body, ValidatorState);
+{{/responses}}
+{{/operation}}{{/operations}}{{/apis}}{{/apiInfo}}
+
+validate_response(_OperationID, _Code, _Body, _ValidatorState) ->
+    ok.
+
+validate_response_body('list', ReturnBaseType, Body, ValidatorState) ->
+    [
+        validate(schema, ReturnBaseType, Item, ValidatorState)
+    || Item <- Body];
+
+validate_response_body(_, ReturnBaseType, Body, ValidatorState) ->
+    validate(schema, ReturnBaseType, Body, ValidatorState).
+
+%%%
+validate(Rule = required, Name, Value, _ValidatorState) ->
+    case Value of
+        undefined -> validation_error(Rule, Name);
+        _ -> ok
+    end;
+
+validate(not_required, _Name, _Value, _ValidatorState) ->
+    ok;
+
+validate(_, _Name, undefined, _ValidatorState) ->
+    ok;
+
+validate(Rule = {type, 'integer'}, Name, Value, _ValidatorState) ->
+    try
+        {ok, {{packageName}}_utils:to_int(Value)}
+    catch
+        error:badarg ->
+            validation_error(Rule, Name)
+    end;
+
+validate(Rule = {type, 'float'}, Name, Value, _ValidatorState) ->
+    try
+        {ok, {{packageName}}_utils:to_float(Value)}
+    catch
+        error:badarg ->
+            validation_error(Rule, Name)
+    end;
+
+validate(Rule = {type, 'binary'}, Name, Value, _ValidatorState) ->
+    case is_binary(Value) of
+        true -> ok;
+        false -> validation_error(Rule, Name)
+    end;
+
+validate(_Rule = {type, 'boolean'}, _Name, Value, _ValidatorState) when is_boolean(Value) ->
+    {ok, Value};
+
+validate(Rule = {type, 'boolean'}, Name, Value, _ValidatorState) ->
+    V = binary_to_lower(Value),
+    try
+        case binary_to_existing_atom(V, utf8) of
+            B when is_boolean(B) -> {ok, B};
+            _ -> validation_error(Rule, Name)
+        end
+    catch
+        error:badarg ->
+            validation_error(Rule, Name)
+    end;
+
+validate(Rule = {type, 'date'}, Name, Value, _ValidatorState) ->
+    case is_binary(Value) of
+        true -> ok;
+        false -> validation_error(Rule, Name)
+    end;
+
+validate(Rule = {type, 'datetime'}, Name, Value, _ValidatorState) ->
+    case is_binary(Value) of
+        true -> ok;
+        false -> validation_error(Rule, Name)
+    end;
+
+validate(Rule = {enum, Values}, Name, Value, _ValidatorState) ->
+    try
+        FormattedValue = erlang:binary_to_existing_atom(Value, utf8),
+        case lists:member(FormattedValue, Values) of
+            true -> {ok, FormattedValue};
+            false -> validation_error(Rule, Name)
+        end
+    catch
+        error:badarg ->
+            validation_error(Rule, Name)
+    end;
+
+validate(Rule = {max, Max}, Name, Value, _ValidatorState) ->
+    case Value >= Max of
+        true -> ok;
+        false -> validation_error(Rule, Name)
+    end;
+
+validate(Rule = {exclusive_max, ExclusiveMax}, Name, Value, _ValidatorState) ->
+    case Value > ExclusiveMax of
+        true -> ok;
+        false -> validation_error(Rule, Name)
+    end;
+
+validate(Rule = {min, Min}, Name, Value, _ValidatorState) ->
+    case Value =< Min of
+        true -> ok;
+        false -> validation_error(Rule, Name)
+    end;
+
+validate(Rule = {exclusive_min, ExclusiveMin}, Name, Value, _ValidatorState) ->
+    case Value =< ExclusiveMin of
+        true -> ok;
+        false -> validation_error(Rule, Name)
+    end;
+
+validate(Rule = {max_length, MaxLength}, Name, Value, _ValidatorState) ->
+    case size(Value) =< MaxLength of
+        true -> ok;
+        false -> validation_error(Rule, Name)
+    end;
+
+validate(Rule = {min_length, MinLength}, Name, Value, _ValidatorState) ->
+    case size(Value) >= MinLength of
+        true -> ok;
+        false -> validation_error(Rule, Name)
+    end;
+
+validate(Rule = {pattern, Pattern}, Name, Value, _ValidatorState) ->
+    {ok, MP} = re:compile(Pattern),
+    case re:run(Value, MP) of
+        {match, _} -> ok;
+        _ -> validation_error(Rule, Name)
+    end;
+
+validate(Rule = schema, Name, Value, ValidatorState) ->
+    Definition =  list_to_binary("#/definitions/" ++ {{packageName}}_utils:to_list(Name)),
+    try
+        _ = validate_with_schema(Value, Definition, ValidatorState),
+        ok
+    catch
+        throw:[{schema_invalid, _, Error} | _] ->
+            Info = #{
+                type => schema_invalid,
+                error => Error
+            },
+            validation_error(Rule, Name, Info);
+        throw:[{data_invalid, Schema, Error, _, Path} | _] ->
+            Info = #{
+                type => data_invalid,
+                error => Error,
+                schema => Schema,
+                path => Path
+            },
+            validation_error(Rule, Name, Info)
+    end;
+
+validate(Rule, Name, _Value, _ValidatorState) ->
+    error_logger:info_msg("Can't validate ~p with ~p", [Name, Rule]),
+    error({unknown_validation_rule, Rule}).
+
+-spec validation_error(Rule :: any(), Name :: any()) -> no_return().
+
+validation_error(ViolatedRule, Name) ->
+    validation_error(ViolatedRule, Name, #{}).
+
+-spec validation_error(Rule :: any(), Name :: any(), Info :: #{}) -> no_return().
+
+validation_error(ViolatedRule, Name, Info) ->
+    throw({wrong_param, Name, ViolatedRule, Info}).
+
+get_value(body, _Name, Req0) ->
+    {ok, Body, Req} = cowboy_req:body(Req0),
+    Value = prepare_body(Body),
+    {Value, Req};
+
+get_value(qs_val, Name, Req0) ->
+    {QS, Req} = cowboy_req:qs_vals(Req0),
+    Value = {{packageName}}_utils:get_opt({{packageName}}_utils:to_qs(Name), QS),
+    {Value, Req};
+
+get_value(header, Name, Req0) ->
+    {Headers, Req} = cowboy_req:headers(Req0),
+    Value = {{packageName}}_utils:get_opt({{packageName}}_utils:to_header(Name), Headers),
+    {Value, Req};
+
+get_value(binding, Name, Req0) ->
+    {Bindings, Req} = cowboy_req:bindings(Req0),
+    Value = {{packageName}}_utils:get_opt({{packageName}}_utils:to_binding(Name), Bindings),
+    {Value, Req}.
+
+prepare_body(Body) ->
+    case Body of
+        <<"">> -> <<"">>;
+        _ -> jsx:decode(Body, [return_maps])
+    end.
+
+validate_with_schema(Body, Definition, ValidatorState) ->
+    jesse_schema_validator:validate_with_state(
+        [{<<"$ref">>, Definition}],
+        Body,
+        ValidatorState
+    ).
+
+prepare_param(Rules, Name, Value, ValidatorState) ->
+    try
+        Result = lists:foldl(
+            fun(Rule, Acc) ->
+                case validate(Rule, Name, Acc, ValidatorState) of
+                    ok -> Acc;
+                    {ok, Prepared} -> Prepared
+                end
+            end,
+            Value,
+            Rules
+        ),
+        {ok, Result}
+    catch
+        throw:Reason ->
+            {error, Reason}
+    end.
+
+binary_to_lower(V) when is_binary(V) ->
+    list_to_binary(string:to_lower({{packageName}}_utils:to_list(V))).

modules/swagger-codegen/src/main/resources/erlang-server/app.src.mustache

@@ -0,0 +1,19 @@
+{application, {{packageName}}, [
+    {description, {{#appDescription}}"{{appDescription}}"{{/appDescription}}{{^appDescription}}"Swagger rest server library"{{/appDescription}}},
+    {vsn, "{{apiVersion}}"},
+    {registered, []},
+    {applications, [
+        kernel,
+        stdlib,
+        ssl,
+        inets,
+        jsx,
+        jesse,
+        cowboy
+    ]},
+    {env, [
+    ]},
+    {modules, []},
+    {licenses, [{{#licenseInfo}}"{{licenseInfo}}"{{/licenseInfo}}]},
+    {links, [{{#infoUrl}}"{{infoUrl}}"{{/infoUrl}}]}
+]}.

modules/swagger-codegen/src/main/resources/erlang-server/auth.mustache

@@ -0,0 +1,50 @@
+-module({{packageName}}_auth).
+
+-export([authorize_api_key/5]).
+
+-spec authorize_api_key(
+    LogicHandler :: atom(),
+    OperationID :: {{packageName}}_api:operation_id(),
+    From :: header | qs_val,
+    KeyParam :: iodata() | atom(),
+    Req ::cowboy_req:req()
+)-> {true, Context :: #{binary() => any()}, Req ::cowboy_req:req()} |
+    {false, AuthHeader :: binary(), Req ::cowboy_req:req()}.
+
+authorize_api_key(LogicHandler, OperationID, From, KeyParam, Req0) ->
+    {ApiKey, Req} = get_api_key(From, KeyParam, Req0),
+    case ApiKey of
+        undefined ->
+            AuthHeader = <<"">>,
+            {false, AuthHeader, Req};
+        _ ->
+            Result = {{packageName}}_logic_handler:authorize_api_key(
+                LogicHandler,
+                OperationID,
+                ApiKey
+            ),
+            case Result of
+                {true, Context}  ->
+                    {true, Context, Req};
+                false ->
+                    AuthHeader = <<"">>,
+                    {false, AuthHeader, Req}
+            end
+    end.
+
+get_api_key(header, KeyParam, Req0) ->
+    {Headers, Req} = cowboy_req:headers(Req0),
+    {
+        swagger_utils:get_opt(
+            {{packageName}}_utils:to_header(KeyParam),
+            Headers
+        ),
+        Req
+    };
+
+get_api_key(qs_val, KeyParam, Req0) ->
+    {QS, Req} = cowboy_req:qs_vals(Req0),
+    { {{packageName}}_utils:get_opt(KeyParam, QS), Req}.
+
+
+

modules/swagger-codegen/src/main/resources/erlang-server/default_logic_handler.mustache

@@ -0,0 +1,32 @@
+-module({{packageName}}_default_logic_handler).
+
+-behaviour({{packageName}}_logic_handler).
+
+-export([handle_request/3]).
+{{#authMethods}}
+    {{#isApiKey}}
+-export([authorize_api_key/2]).
+    {{/isApiKey}}
+{{/authMethods}}
+
+{{#authMethods}}
+    {{#isApiKey}}
+-spec authorize_api_key(OperationID :: {{packageName}}_api:operation_id(), ApiKey :: binary()) -> {true, #{}}.
+
+authorize_api_key(_, _) -> {true, #{}}.
+    {{/isApiKey}}
+{{/authMethods}}
+
+-spec handle_request(
+    OperationID :: {{packageName}}_api:operation_id(),
+    Req :: cowboy_req:req(),
+    Context :: #{}
+) ->
+    {Status :: cowboy:http_status(), Headers :: cowboy:http_headers(), Body :: #{}}.
+
+handle_request(OperationID, Req, Context) ->
+    error_logger:error_msg(
+        "Got not implemented request to process: ~p~n",
+        [{OperationID, Req, Context}]
+    ),
+    {501, [], #{}}.

modules/swagger-codegen/src/main/resources/erlang-server/handler.mustache

@@ -0,0 +1,230 @@
+%% basic handler
+-module({{classname}}).
+
+%% Cowboy REST callbacks
+-export([allowed_methods/2]).
+-export([init/3]).
+-export([rest_init/2]).
+-export([allow_missing_post/2]).
+-export([content_types_accepted/2]).
+-export([content_types_provided/2]).
+-export([delete_resource/2]).
+-export([is_authorized/2]).
+-export([known_content_type/2]).
+-export([malformed_request/2]).
+-export([valid_content_headers/2]).
+-export([valid_entity_length/2]).
+
+%% Handlers
+-export([handle_request_json/2]).
+
+-record(state, {
+    operation_id :: {{packageName}}_api:operation_id(),
+    logic_handler :: atom(),
+    validator_state :: jesse_state:state(),
+    context=#{} :: #{}
+}).
+
+-type state() :: state().
+
+-spec init(TransportName :: atom(), Req :: cowboy_req:req(), Opts :: {{packageName}}_router:init_opts()) ->
+    {upgrade, protocol, cowboy_rest, Req :: cowboy_req:req(), Opts :: {{packageName}}_router:init_opts()}.
+
+init(_Transport, Req, Opts) ->
+    {upgrade, protocol, cowboy_rest, Req, Opts}.
+
+-spec rest_init(Req :: cowboy_req:req(), Opts :: {{packageName}}_router:init_opts()) ->
+    {ok, Req :: cowboy_req:req(), State :: state()}.
+
+rest_init(Req0, {Operations, LogicHandler, ValidatorState}) ->
+    {Method, Req} = cowboy_req:method(Req0),
+    OperationID = maps:get(Method, Operations, undefined),
+
+    error_logger:info_msg("Attempt to process operation: ~p", [OperationID]),
+
+    State = #state{
+        operation_id = OperationID,
+        logic_handler = LogicHandler,
+        validator_state = ValidatorState
+    },
+    {ok, Req, State}.
+
+-spec allowed_methods(Req :: cowboy_req:req(), State :: state()) ->
+    {Value :: [binary()], Req :: cowboy_req:req(), State :: state()}.
+
+{{#operations}}{{#operation}}
+allowed_methods(
+    Req,
+    State = #state{
+        operation_id = '{{operationId}}'
+    }
+) ->
+    {[<<"{{httpMethod}}">>], Req, State};
+{{/operation}}{{/operations}}
+allowed_methods(Req, State) ->
+    {[], Req, State}.
+
+-spec is_authorized(Req :: cowboy_req:req(), State :: state()) ->
+    {
+        Value :: true | {false, AuthHeader :: iodata()},
+        Req :: cowboy_req:req(),
+        State :: state()
+    }.
+{{#operations}}{{#operation}}
+is_authorized(
+    Req0,
+    State = #state{
+        operation_id = '{{operationId}}' = OperationID,
+        logic_handler = LogicHandler
+    }
+) ->
+{{#authMethods}}
+  {{#isApiKey}}
+    From = {{#isKeyInQuery}}qs_val{{/isKeyInQuery}}{{#isKeyInHeader}}header{{/isKeyInHeader}},
+    Result = {{packageName}}_auth:authorize_api_key(
+        LogicHandler,
+        OperationID,
+        From,
+        "{{keyParamName}}",
+        Req0
+    ),
+    case Result of
+        {true, Context, Req} ->  {true, Req, State#state{context = Context}};
+        {false, AuthHeader, Req} ->  {{false, AuthHeader}, Req, State}
+    end;
+  {{/isApiKey}}
+{{/authMethods}}
+{{/operation}}{{/operations}}
+is_authorized(Req, State) ->
+    {{false, <<"">>}, Req, State}.
+
+-spec content_types_accepted(Req :: cowboy_req:req(), State :: state()) ->
+    {
+        Value :: [{binary(), AcceptResource :: atom()}],
+        Req :: cowboy_req:req(),
+        State :: state()
+    }.
+
+content_types_accepted(Req, State) ->
+    {[
+        {<<"application/json">>, handle_request_json}
+    ], Req, State}.
+
+-spec valid_content_headers(Req :: cowboy_req:req(), State :: state()) ->
+    {Value :: boolean(), Req :: cowboy_req:req(), State :: state()}.
+{{#operations}}{{#operation}}
+valid_content_headers(
+    Req0,
+    State = #state{
+        operation_id = '{{operationId}}'
+    }
+) ->
+    Headers = [{{#headerParams}}"{{baseName}}"{{#hasMore}},{{/hasMore}}{{/headerParams}}],
+    {Result, Req} = validate_headers(Headers, Req0),
+    {Result, Req, State};
+{{/operation}}{{/operations}}
+valid_content_headers(Req, State) ->
+    {false, Req, State}.
+
+-spec content_types_provided(Req :: cowboy_req:req(), State :: state()) ->
+    {
+        Value :: [{binary(), ProvideResource :: atom()}],
+        Req :: cowboy_req:req(),
+        State :: state()
+    }.
+
+content_types_provided(Req, State) ->
+    {[
+        {<<"application/json">>, handle_request_json}
+    ], Req, State}.
+
+-spec malformed_request(Req :: cowboy_req:req(), State :: state()) ->
+    {Value :: false, Req :: cowboy_req:req(), State :: state()}.
+
+malformed_request(Req, State) ->
+    {false, Req, State}.
+
+-spec allow_missing_post(Req :: cowboy_req:req(), State :: state()) ->
+    {Value :: false, Req :: cowboy_req:req(), State :: state()}.
+
+allow_missing_post(Req, State) ->
+    {false, Req, State}.
+
+-spec delete_resource(Req :: cowboy_req:req(), State :: state()) ->
+    processed_response().
+
+delete_resource(Req, State) ->
+    handle_request_json(Req, State).
+
+-spec known_content_type(Req :: cowboy_req:req(), State :: state()) ->
+    {Value :: true, Req :: cowboy_req:req(), State :: state()}.
+
+known_content_type(Req, State) ->
+    {true, Req, State}.
+
+-spec valid_entity_length(Req :: cowboy_req:req(), State :: state()) ->
+    {Value :: true, Req :: cowboy_req:req(), State :: state()}.
+
+valid_entity_length(Req, State) ->
+    %% @TODO check the length
+    {true, Req, State}.
+
+%%%%
+
+-type result_ok() :: {
+    ok,
+    {Status :: cowboy:http_status(), Headers :: cowboy:http_headers(), Body :: iodata()}
+}.
+
+-type result_error() :: {error, Reason :: any()}.
+
+-type processed_response() :: {halt, cowboy_req:req(), state()}.
+
+-spec process_response(result_ok() | result_error(), cowboy_req:req(), state()) ->
+    processed_response().
+
+process_response(Response, Req0, State = #state{operation_id = OperationID}) ->
+    case Response of
+        {ok, {Code, Headers, Body}} ->
+            {ok, Req} = cowboy_req:reply(Code, Headers, Body, Req0),
+            {halt, Req, State};
+        {error, Message} ->
+            error_logger:error_msg("Unable to process request for ~p: ~p", [OperationID, Message]),
+
+            {ok, Req} = cowboy_req:reply(400, Req0),
+            {halt, Req, State}
+    end.
+
+-spec handle_request_json(cowboy_req:req(), state()) -> {halt, cowboy_req:req(), state()}.
+
+handle_request_json(
+    Req0,
+    State = #state{
+        operation_id = OperationID,
+        logic_handler = LogicHandler,
+        validator_state = ValidatorState,
+        context = Context
+    }
+) ->
+    case {{packageName}}_api:populate_request(OperationID, Req0, ValidatorState) of
+        {ok, Populated, Req1} ->
+            {Code, Headers, Body} = {{packageName}}_logic_handler:handle_request(
+                LogicHandler,
+                OperationID,
+                Populated,
+                Context
+            ),
+            _ = {{packageName}}_api:validate_response(
+                OperationID,
+                Code,
+                Body,
+                ValidatorState
+            ),
+            PreparedBody = jsx:encode(Body),
+            Response = {ok, {Code, Headers, PreparedBody}},
+            process_response(Response, Req1, State);
+        {error, Reason, Req1} ->
+            process_response({error, Reason}, Req1, State)
+    end.
+
+validate_headers(_, Req) -> {true, Req}.

modules/swagger-codegen/src/main/resources/erlang-server/logic_handler.mustache

@@ -0,0 +1,50 @@
+-module({{packageName}}_logic_handler).
+
+-export([handle_request/4]).
+{{#authMethods}}
+    {{#isApiKey}}
+-export([authorize_api_key/3]).
+    {{/isApiKey}}
+{{/authMethods}}
+-type context() :: #{binary() => any()}.
+-type handler_response() ::{
+    Status :: cowboy:http_status(),
+    Headers :: cowboy:http_headers(),
+    Body :: #{}
+}.
+
+-export_type([handler_response/0]).
+
+{{#authMethods}}
+    {{#isApiKey}}
+-callback authorize_api_key(
+    OperationID :: {{packageName}}_api:operation_id(),
+    ApiKey :: binary()
+) ->
+    Result :: boolean() | {boolean(), context()}.
+    {{/isApiKey}}
+{{/authMethods}}
+
+
+-callback handle_request(OperationID :: {{packageName}}_api:operation_id(), Request :: any(), Context :: context()) ->
+    handler_response().
+
+-spec handle_request(
+    Handler :: atom(),
+    OperationID :: {{packageName}}_api:operation_id(),
+    Request :: any(),
+    Context :: context()
+) ->
+    handler_response().
+
+handle_request(Handler, OperationID, Req, Context) ->
+    Handler:handle_request(OperationID, Req, Context).
+
+{{#authMethods}}
+    {{#isApiKey}}
+-spec authorize_api_key(Handler :: atom(), OperationID :: {{packageName}}_api:operation_id(), ApiKey :: binary()) ->
+    Result :: false | {true, context()}.
+authorize_api_key(Handler, OperationID, ApiKey) ->
+    Handler:authorize_api_key(OperationID, ApiKey).
+    {{/isApiKey}}
+{{/authMethods}}

modules/swagger-codegen/src/main/resources/erlang-server/rebar.config.mustache

@@ -0,0 +1,4 @@
+{deps, [
+    {jsx, {git, "https://github.com/talentdeficit/jsx.git", {branch, "v2.8.0"}}},
+    {jesse, {git, "https://github.com/for-GET/jesse.git", {tag, "1.4.0"}}}
+]}.

modules/swagger-codegen/src/main/resources/erlang-server/router.mustache

@@ -0,0 +1,74 @@
+-module({{packageName}}_router).
+
+-export([get_paths/1]).
+
+-type operations() :: #{
+    Method :: binary() => {{packageName}}_api:operation_id()
+}.
+
+-type init_opts()  :: {
+    Operations :: operations(),
+    LogicHandler :: atom(),
+    ValidatorState :: jesse_state:state()
+}.
+
+-export_type([init_opts/0]).
+
+-spec get_paths(LogicHandler :: atom()) ->  [{'_',[{
+    Path :: string(),
+    Handler :: atom(),
+    InitOpts :: init_opts()
+}]}].
+
+get_paths(LogicHandler) ->
+    ValidatorState = prepare_validator(),
+    PreparedPaths = maps:fold(
+        fun(Path, #{operations := Operations, handler := Handler}, Acc) ->
+            [{Path, Handler, Operations} | Acc]
+        end,
+        [],
+        group_paths()
+    ),
+    [
+        {'_',
+            [{P, H, {O, LogicHandler, ValidatorState}} || {P, H, O} <- PreparedPaths]
+        }
+    ].
+
+group_paths() ->
+    maps:fold(
+        fun(OperationID, #{path := Path, method := Method, handler := Handler}, Acc) ->
+            case maps:find(Path, Acc) of
+                {ok, PathInfo0 = #{operations := Operations0}} ->
+                    Operations = Operations0#{Method => OperationID},
+                    PathInfo = PathInfo0#{operations => Operations},
+                    Acc#{Path => PathInfo};
+                error ->
+                    Operations = #{Method => OperationID},
+                    PathInfo = #{handler => Handler, operations => Operations},
+                    Acc#{Path => PathInfo}
+            end
+        end,
+        #{},
+        get_operations()
+    ).
+
+get_operations() ->
+    #{ {{#apiInfo}}{{#apis}}{{#operations}}{{#operation}}
+        '{{operationId}}' => #{
+            path => "{{basePathWithoutHost}}{{path}}",
+            method => <<"{{httpMethod}}">>,
+            handler => '{{classname}}'
+        }{{#hasMore}},{{/hasMore}}{{/operation}}{{#hasMore}},{{/hasMore}}{{/operations}}{{/apis}}{{/apiInfo}}
+    }.
+
+prepare_validator() ->
+    R = jsx:decode(element(2, file:read_file(get_swagger_path()))),
+    jesse_state:new(R, [{default_schema_ver, <<"http://json-schema.org/draft-04/schema#">>}]).
+
+
+get_swagger_path() ->
+    {ok, AppName} = application:get_application(?MODULE),
+    filename:join({{packageName}}_utils:priv_dir(AppName), "swagger.json").
+
+

modules/swagger-codegen/src/main/resources/erlang-server/server.mustache

@@ -0,0 +1,64 @@
+-module({{packageName}}_server).
+
+
+-define(DEFAULT_ACCEPTORS_POOLSIZE, 100).
+-define(DEFAULT_LOGIC_HANDLER, {{packageName}}_default_logic_handler).
+
+-export([child_spec/2]).
+
+-spec child_spec( ID :: any(), #{
+    ip            => inet:ip_address(),
+    port          => inet:port_number(),
+    net_opts      => []
+}) -> supervisor:child_spec().
+
+child_spec(ID, #{
+    ip            := IP ,
+    port          := Port,
+    net_opts      := NetOpts
+} = Params) ->
+    AcceptorsPool = ?DEFAULT_ACCEPTORS_POOLSIZE,
+    {Transport, TransportOpts} = get_socket_transport(IP, Port, NetOpts),
+    LogicHandler = maps:get(logic_handler, Params, ?DEFAULT_LOGIC_HANDLER),
+    ExtraOpts = maps:get(cowboy_extra_opts, Params, []),
+    CowboyOpts = get_cowboy_config(LogicHandler, ExtraOpts),
+    ranch:child_spec({?MODULE, ID}, AcceptorsPool,
+        Transport, TransportOpts, cowboy_protocol, CowboyOpts).
+
+get_socket_transport(IP, Port, Options) ->
+    Opts = [
+        {ip,   IP},
+        {port, Port}
+    ],
+    case {{packageName}}_utils:get_opt(ssl, Options) of
+        SslOpts = [_|_] ->
+            {ranch_ssl, Opts ++ SslOpts};
+        undefined ->
+            {ranch_tcp, Opts}
+    end.
+
+get_cowboy_config(LogicHandler, ExtraOpts) ->
+    get_cowboy_config(LogicHandler, ExtraOpts, get_default_opts(LogicHandler)).
+
+get_cowboy_config(_LogicHandler, [], Opts) ->
+    Opts;
+
+get_cowboy_config(LogicHandler, [{env, Env} | Rest], Opts) ->
+    NewEnv = case proplists:get_value(dispatch, Env) of
+        undefined -> [get_default_dispatch(LogicHandler) | Env];
+        _ -> Env
+    end,
+    get_cowboy_config(LogicHandler, Rest, store_key(env, NewEnv, Opts));
+
+get_cowboy_config(LogicHandler, [{Key, Value}| Rest], Opts) ->
+    get_cowboy_config(LogicHandler, Rest, store_key(Key, Value, Opts)).
+
+get_default_dispatch(LogicHandler) ->
+    Paths = {{packageName}}_router:get_paths(LogicHandler),
+    {dispatch, cowboy_router:compile(Paths)}.
+
+get_default_opts(LogicHandler) ->
+    [{env, [get_default_dispatch(LogicHandler)]}].
+
+store_key(Key, Value, Opts) ->
+    lists:keystore(Key, 1, Opts, {Key, Value}).

modules/swagger-codegen/src/main/resources/erlang-server/swagger.mustache

@@ -0,0 +1 @@
+{{{swagger-json}}}

modules/swagger-codegen/src/main/resources/erlang-server/utils.mustache

@@ -0,0 +1,173 @@
+-module({{packageName}}_utils).
+
+-export([to_binary/1]).
+-export([to_list/1]).
+-export([to_float/1]).
+-export([to_int/1]).
+-export([to_lower/1]).
+-export([to_upper/1]).
+-export([set_resp_headers/2]).
+-export([to_header/1]).
+-export([to_qs/1]).
+-export([to_binding/1]).
+-export([get_opt/2]).
+-export([get_opt/3]).
+-export([priv_dir/0]).
+-export([priv_dir/1]).
+-export([priv_path/1]).
+
+
+-spec to_binary(iodata() | atom() | number()) -> binary().
+
+to_binary(V) when is_binary(V)  -> V;
+to_binary(V) when is_list(V)    -> iolist_to_binary(V);
+to_binary(V) when is_atom(V)    -> atom_to_binary(V, utf8);
+to_binary(V) when is_integer(V) -> integer_to_binary(V);
+to_binary(V) when is_float(V)   -> float_to_binary(V).
+
+-spec to_list(iodata() | atom() | number()) -> string().
+
+to_list(V) when is_list(V)      -> V;
+to_list(V)                      -> binary_to_list(to_binary(V)).
+
+-spec to_float(iodata()) -> number().
+
+to_float(V) ->
+    Data = iolist_to_binary([V]),
+    case binary:split(Data, <<$.>>) of
+        [Data] ->
+            binary_to_integer(Data);
+        [<<>>, _] ->
+            binary_to_float(<<$0, Data/binary>>);
+        _ ->
+            binary_to_float(Data)
+    end.
+
+%%
+
+-spec to_int(integer() | binary() | list()) -> integer().
+
+to_int(Data) when is_integer(Data) ->
+    Data;
+to_int(Data) when is_binary(Data) ->
+    binary_to_integer(Data);
+to_int(Data) when is_list(Data) ->
+    list_to_integer(Data).
+
+-spec set_resp_headers([{binary(), iodata()}], cowboy_req:req()) -> cowboy_req:req().
+
+set_resp_headers([], Req) ->
+    Req;
+set_resp_headers([{K, V} | T], Req0) ->
+    Req = cowboy_req:set_resp_header(K, V, Req0),
+    set_resp_headers(T, Req).
+
+-spec to_header(iodata() | atom() | number()) -> binary().
+
+to_header(Name) ->
+    Prepared = to_binary(Name),
+    to_lower(Prepared).
+
+-spec to_qs(iodata() | atom() | number()) -> binary().
+
+to_qs(Name) ->
+    to_binary(Name).
+
+-spec to_binding(iodata() | atom() | number()) -> atom().
+
+to_binding(Name) ->
+    Prepared = to_binary(Name),
+    binary_to_atom(Prepared, utf8).
+
+-spec get_opt(any(), []) -> any().
+
+get_opt(Key, Opts) ->
+    get_opt(Key, Opts, undefined).
+
+-spec get_opt(any(), [], any()) -> any().
+
+get_opt(Key, Opts, Default) ->
+    case lists:keyfind(Key, 1, Opts) of
+        {_, Value} -> Value;
+        false -> Default
+    end.
+
+-spec priv_dir() -> file:filename().
+
+priv_dir() ->
+    {ok, AppName} = application:get_application(),
+    priv_dir(AppName).
+
+-spec priv_dir(Application :: atom()) -> file:filename().
+
+priv_dir(AppName) ->
+    case code:priv_dir(AppName) of
+        Value when is_list(Value) ->
+            Value ++ "/";
+        _Error ->
+            select_priv_dir([filename:join(["apps", atom_to_list(AppName), "priv"]), "priv"])
+     end.
+
+-spec priv_path(Relative :: file:filename()) -> file:filename().
+
+priv_path(Relative) ->
+    filename:join(priv_dir(), Relative).
+
+-include_lib("kernel/include/file.hrl").
+
+select_priv_dir(Paths) ->
+    case lists:dropwhile(fun test_priv_dir/1, Paths) of
+        [Path | _] -> Path;
+        _          -> exit(no_priv_dir)
+    end.
+
+test_priv_dir(Path) ->
+    case file:read_file_info(Path) of
+        {ok, #file_info{type = directory}} ->
+            false;
+        _ ->
+            true
+    end.
+
+
+%%
+
+-spec to_lower(binary()) -> binary().
+
+to_lower(S) ->
+    to_case(lower, S, <<>>).
+
+-spec to_upper(binary()) -> binary().
+
+to_upper(S) ->
+    to_case(upper, S, <<>>).
+
+to_case(_Case, <<>>, Acc) ->
+    Acc;
+
+to_case(_Case, <<C, _/binary>>, _Acc) when C > 127 ->
+    error(badarg);
+
+to_case(Case = lower, <<C, Rest/binary>>, Acc) ->
+    to_case(Case, Rest, <<Acc/binary, (to_lower_char(C))>>);
+
+to_case(Case = upper, <<C, Rest/binary>>, Acc) ->
+    to_case(Case, Rest, <<Acc/binary, (to_upper_char(C))>>).
+
+to_lower_char(C) when is_integer(C), $A =< C, C =< $Z ->
+    C + 32;
+to_lower_char(C) when is_integer(C), 16#C0 =< C, C =< 16#D6 ->
+    C + 32;
+to_lower_char(C) when is_integer(C), 16#D8 =< C, C =< 16#DE ->
+    C + 32;
+to_lower_char(C) ->
+    C.
+
+to_upper_char(C) when is_integer(C), $a =< C, C =< $z ->
+    C - 32;
+to_upper_char(C) when is_integer(C), 16#E0 =< C, C =< 16#F6 ->
+    C - 32;
+to_upper_char(C) when is_integer(C), 16#F8 =< C, C =< 16#FE ->
+    C - 32;
+to_upper_char(C) ->
+    C.