[Eiffel] Add Eiffel API client generator (#6036)

* Initial Eiffel Client code generator
TODO API and Domain model

* Updated EiffelClientCodegen to support Eiffel code style.
Added mustaches templates for models and apis.
The last one still under development.

* Updated templates, initial API generation.
Added client request template.

* Updated api.mustache style

* Updated code generation with a new directory layout.
Added test case generation, clean code.

* Updated Code generator, added apidoc and modeldoc
Updated readme file

* Added a Basic JSON Deserializer
Updated API client to support by default a basic json (de)serializer and let
the user customize then if needed.

* Updated Eiffel code generator to use Eiffel feature name style.
Updated templates to follow Eiffel style.
Improved feature descriptions.

* Added model inheritance support.
Removed unused code.

* Updated Eiffel code templates, refactor remove obsolte feature calls.
Added Eiffel sample in samples/client/petstore/eiffel.

* Updated Java code style.

* Fixed formating, using spaces instead of tabs.

* Updated EiffelCodeGenarator typeMapping.
Added TestCases for EfiffelClientOption and ModelTest cases.
Updated sample code to use the lastest changes.

* Restore keyword `nil' in Go Language.

Author: jvelilla

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

@@ -56,8 +56,7 @@ public GoClientCodegen() {
                 "case", "defer", "go", "map", "struct",
                 "chan", "else", "goto", "package", "switch",
                 "const", "fallthrough", "if", "range", "type",
-                "continue", "for", "import", "return", "var", "error", "ApiResponse",
-                "nil")
+                "continue", "for", "import", "return", "var", "error", "ApiResponse", "nil")
                 // Added "error" as it's used so frequently that it may as well be a keyword
         );
 

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

@@ -0,0 +1,65 @@
+# Eiffel API client for {{packageName}}
+
+{{#appDescription}}
+{{{appDescription}}}
+{{/appDescription}}
+
+## Overview
+This API client was generated by the [swagger-codegen](https://github.com/swagger-api/swagger-codegen) project.  By using the [swagger-spec](https://github.com/swagger-api/swagger-spec) from a remote server, you can easily generate an API client.
+
+- API version: {{appVersion}}
+- Package version: {{packageVersion}}
+{{^hideGenerationTimestamp}}
+- Build date: {{generatedDate}}
+{{/hideGenerationTimestamp}}
+- Build package: {{generatorClass}}
+{{#infoUrl}}
+For more information, please visit [{{{infoUrl}}}]({{{infoUrl}}})
+{{/infoUrl}}
+
+## Installation
+Add the library into your Eiffel configuration file.
+```
+    "<library name="api_client" location="%PATH_TO_EIFFEL_SWAGGER_CLIENT%\api_client.ecf"/>"
+```
+
+## Documentation for API Endpoints
+
+All URIs are relative to *{{basePath}}*
+
+Class | Method | HTTP request | Description
+------------ | ------------- | ------------- | -------------
+{{#apiInfo}}{{#apis}}{{#operations}}{{#operation}}*{{classname}}* | [**{{operationId}}**]({{apiDocPath}}{{classname}}.md#{{operationIdLowerCase}}) | **{{httpMethod}}** {{path}} | {{#summary}}{{summary}}{{/summary}}
+{{/operation}}{{/operations}}{{/apis}}{{/apiInfo}}
+
+## Documentation For Models
+
+{{#models}}{{#model}} - [{{{classname}}}]({{modelDocPath}}{{{classname}}}.md)
+{{/model}}{{/models}}
+
+## Documentation For Authorization
+
+{{^authMethods}} All endpoints do not require authorization.
+{{/authMethods}}{{#authMethods}}{{#last}} Authentication schemes defined for the API:{{/last}}{{/authMethods}}
+{{#authMethods}}## {{{name}}}
+
+{{#isApiKey}}- **Type**: API key 
+- **API key parameter name**: {{{keyParamName}}}
+- **Location**: {{#isKeyInQuery}}URL query string{{/isKeyInQuery}}{{#isKeyInHeader}}HTTP header{{/isKeyInHeader}}
+{{/isApiKey}}
+{{#isBasic}}- **Type**: HTTP basic authentication
+{{/isBasic}}
+{{#isOAuth}}- **Type**: OAuth
+- **Flow**: {{{flow}}}
+- **Authorization URL**: {{{authorizationUrl}}}
+- **Scopes**: {{^scopes}}N/A{{/scopes}}
+{{#scopes}} - **{{{scope}}}**: {{{description}}}
+{{/scopes}}
+{{/isOAuth}}
+
+{{/authMethods}}
+
+## Author
+
+{{#apiInfo}}{{#apis}}{{^hasMore}}{{infoEmail}}
+{{/hasMore}}{{/apis}}{{/apiInfo}}

modules/swagger-codegen/src/main/resources/Eiffel/README.mustache

@@ -0,0 +1,75 @@
+{{>noteinfo}}
+{{#operations}}
+
+class
+	{{classname}}
+
+inherit
+
+    API_I
+
+
+feature -- API Access
+
+{{#operation}}
+
+	{{operationId}} {{#hasParams}}({{#allParams}}{{paramName}}: {{#required}}{{{dataType}}}{{/required}}{{^required}}detachable {{{dataType}}}{{/required}}{{#hasMore}}; {{/hasMore}}{{/allParams}}){{/hasParams}}{{#returnType}}: detachable {{{returnType}}}{{/returnType}}{{^returnType}}{{/returnType}}
+			-- {{summary}}
+			-- {{notes}}
+			-- {{#allParams}}
+			-- argument: {{paramName}} {{description}}{{#required}} (required){{/required}}{{^required}} (optional{{#defaultValue}}, default to {{{.}}}{{/defaultValue}}){{/required}}
+			-- {{/allParams}}
+			-- {{#returnType}}
+			-- Result {{returnType}}{{/returnType}}
+		local
+  			l_path: STRING
+  			l_request: API_CLIENT_REQUEST
+  			l_response: API_CLIENT_RESPONSE
+		do
+			reset_error
+			create l_request
+			{{#bodyParam}}l_request.set_body({{paramName}}){{/bodyParam}}
+			l_path := "{{{path}}}"
+			{{#pathParams}}
+			l_path.replace_substring_all ("{"+"{{baseName}}"+"}", api_client.url_encode ({{{paramName}}}.out))
+			{{/pathParams}}
+			{{#queryParams}}
+			l_request.fill_query_params(api_client.parameter_to_tuple("{{#collectionFormat}}{{{collectionFormat}}}{{/collectionFormat}}", "{{baseName}}", {{paramName}}));
+			{{/queryParams}}
+			{{#headerParams}}
+			if attached {{paramName}} as l_{{paramName}} then
+				l_request.add_header(l_{{paramName}}.out,"{{baseName}}");
+			end
+			{{/headerParams}}
+			{{#formParams}}
+			if attached {{paramName}} as l_{{paramName}} then
+				l_request.add_form(l_{{paramName}},"{{baseName}}");
+			end
+			{{/formParams}}
+
+			if attached {STRING} api_client.select_header_accept (<<{{#produces}}"{{{mediaType}}}"{{#hasMore}}, {{/hasMore}}{{/produces}}>>)  as l_accept then
+				l_request.add_header(l_accept,"Accept");
+			end
+			l_request.add_header(api_client.select_header_content_type (<<{{#consumes}}"{{{mediaType}}}"{{#hasMore}}, {{/hasMore}}{{/consumes}}>>),"Content-Type")
+			l_request.set_auth_names (<<{{#authMethods}}"{{name}}"{{#hasMore}}, {{/hasMore}}{{/authMethods}}>>)
+			l_response := api_client.call_api (l_path, "{{httpMethod}}", l_request, {{#returnType}}Void{{/returnType}}{{^returnType}}agent serializer{{/returnType}}, {{#returnType}}agent deserializer{{/returnType}}{{^returnType}}Void{{/returnType}})
+			{{#returnType}}	
+			if l_response.has_error then
+				last_error := l_response.error
+			elseif attached { {{{returnType}}} } l_response.data ({ {{{returnType}}} }) as l_data then
+				Result := l_data
+			else
+				create last_error.make ("Unknown error: Status response [ " + l_response.status.out + "]")
+			end
+			{{/returnType}}
+			{{^returnType}}
+			if l_response.has_error then
+				last_error := l_response.error
+			end
+			{{/returnType}}
+		end	
+{{/operation}}
+
+
+end
+{{/operations}}