Merge pull request #2295 from neilotoole/issue-2292

Re #2292 : The generated API should now return an err for non-2xx status codes

modules/swagger-codegen/src/main/resources/go/api.mustache

@@ -4,6 +4,8 @@ package {{packageName}}
 import (
     "strings"
     "fmt"
+    "encoding/json"
+    "errors"
     "github.com/dghubble/sling"
 {{#imports}}    "{{import}}"
 {{/imports}}
@@ -68,16 +70,39 @@ func (a {{classname}}) {{nickname}} ({{#allParams}}{{paramName}} {{{dataType}}}{
 {{#hasBodyParam}}{{#bodyParams}}// body params
     _sling = _sling.BodyJSON({{paramName}})
 {{/bodyParams}}{{/hasBodyParam}}
+{{#returnType}}  var successPayload = new({{returnType}}){{/returnType}}
 
-{{#returnType}}    response := new({{returnType}})
-    _, err := _sling.ReceiveSuccess(response)
-    //fmt.Println("{{operationId}} response: ", response, resp, err)
-    return *response, err
-{{/returnType}}{{^returnType}}
-    _, err := _sling.ReceiveSuccess(nil)
-    //fmt.Println("{{operationId}} response: void, ", resp, err)
-    return err
-{{/returnType}}
+  // We use this map (below) so that any arbitrary error JSON can be handled.
+  // FIXME: This is in the absence of this Go generator honoring the non-2xx
+  // response (error) models, which needs to be implemented at some point.
+  var failurePayload map[string]interface{}
+
+  httpResponse, err := _sling.Receive({{#returnType}}successPayload{{/returnType}}{{^returnType}}nil{{/returnType}}, &failurePayload)
+
+  if err == nil {
+    // err == nil only means that there wasn't a sub-application-layer error (e.g. no network error)
+    if failurePayload != nil {
+      // If the failurePayload is present, there likely was some kind of non-2xx status
+      // returned (and a JSON payload error present)
+      var str []byte
+      str, err = json.Marshal(failurePayload)
+      if err == nil { // For safety, check for an error marshalling... probably superfluous
+        // This will return the JSON error body as a string
+        err = errors.New(string(str))
+      }
+  } else {
+    // So, there was no network-type error, and nothing in the failure payload,
+    // but we should still check the status code
+    if httpResponse == nil {
+      // This should never happen...
+      err = errors.New("No HTTP Response received.")
+    } else if code := httpResponse.StatusCode; 200 > code || code > 299 {
+        err = errors.New("HTTP Error: " + string(httpResponse.StatusCode))
+      }
+    }
+  }
+
+  return {{#returnType}}*successPayload, {{/returnType}}err
 }
 {{/operation}}
 {{/operations}}