Update pattern to support Perl /pattern/modifiers convention

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

@@ -3,15 +3,21 @@ package io.swagger.codegen.languages;
 import io.swagger.codegen.CliOption;
 import io.swagger.codegen.CodegenConfig;
 import io.swagger.codegen.CodegenConstants;
+import io.swagger.codegen.CodegenModel;
 import io.swagger.codegen.CodegenParameter;
+import io.swagger.codegen.CodegenProperty;
 import io.swagger.codegen.CodegenType;
 import io.swagger.codegen.DefaultCodegen;
 import io.swagger.codegen.SupportingFile;
 import io.swagger.models.properties.*;
 
 import java.io.File;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
 
 import org.apache.commons.lang.StringUtils;
 
@@ -21,6 +27,8 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
     protected String apiDocPath = "docs/";
     protected String modelDocPath = "docs/";
     
+    protected Map<Character, String> regexModifiers;
+    
 	private String testFolder;
 
     public PythonClientCodegen() {
@@ -87,6 +95,14 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
                     "assert", "else", "if", "pass", "yield", "break", "except", "import",
                     "print", "class", "exec", "in", "raise", "continue", "finally", "is",
                     "return", "def", "for", "lambda", "try", "self"));
+        
+        regexModifiers = new HashMap<Character, String>();
+        regexModifiers.put('i', "IGNORECASE");
+        regexModifiers.put('l', "LOCALE");
+        regexModifiers.put('m', "MULTILINE");
+        regexModifiers.put('s', "DOTALL");
+        regexModifiers.put('u', "UNICODE");
+        regexModifiers.put('x', "VERBOSE");
 
         cliOptions.clear();
         cliOptions.add(new CliOption(CodegenConstants.PACKAGE_NAME, "python package name (convention: snake_case).")
@@ -143,6 +159,46 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
     private static String dropDots(String str) {
         return str.replaceAll("\\.", "_");
     }
+    
+    @Override
+    public void postProcessParameter(CodegenParameter parameter){
+    	postProcessPattern(parameter.pattern, parameter.vendorExtensions);
+    }
+    
+    @Override
+    public void postProcessModelProperty(CodegenModel model, CodegenProperty property) {
+    	postProcessPattern(property.pattern, property.vendorExtensions);
+    }
+
+	/*
+	 * The swagger pattern spec follows the Perl convention and style of modifiers. Python
+	 * does not support this in as natural a way so it needs to convert it. See
+	 * https://docs.python.org/2/howto/regex.html#compilation-flags for details.
+	 */
+    public void postProcessPattern(String pattern, Map<String, Object> vendorExtensions){
+    	if(pattern != null) {
+    		int i = pattern.lastIndexOf('/');
+    		
+    		//Must follow Perl /pattern/modifiers convention
+    		if(pattern.charAt(0) != '/' || i < 2) {
+    			throw new IllegalArgumentException("Pattern must follow the Perl "
+    					+ "/pattern/modifiers convention. "+pattern+" is not valid.");
+    		}
+
+    		String regex = pattern.substring(1, i).replace("'", "\'");
+    		List<String> modifiers = new ArrayList<String>();
+
+    		for(char c : pattern.substring(i).toCharArray()) {
+    			if(regexModifiers.containsKey(c)) {
+    				String modifier = regexModifiers.get(c);
+    				modifiers.add(modifier);
+    			}
+    		}
+
+    		vendorExtensions.put("x-regex", regex);
+    		vendorExtensions.put("x-modifiers", modifiers);
+    	}
+    }
 
     @Override
     public CodegenType getTag() {