API2Swagger

Manual generation and maintenance of Swagger JSON for REST services can be painful because you have to provide too many details about a REST service. To avoid this manual work we have developed API2Swagger tool to generate Swagger JSON automatically by invoking REST service(s).

Features!

• Swagger JSON generation using builders
• Swagger JSON generation using command line utility
• JSON schema generation from JSON response data
• Capability of updating existing Swagger JSON document with new API
• Capability of modifying existing Swagger JSON with API related modifications - which includes adding new request parameters, response changes
• Capability of recognizing 'FILE' downloads via REST API because Swagger JSON document has special way treating for FILE downloads

Installation

To build the project including standalone jar

./gradlew clean buildall

Built library can be found under <root-project>/build/libs.

• api2swagger-1.0.jar is a binary that can be used in other applications as a library
• api2swagger-all-1.0.jar is a binary to be used as a standalone application

Command Line Arguments

Various command line options are:

Argument	Human Readable Form	Description
-e	--endpoint	specify endpoint URL, this URL will be invoked and response will be generated.
-o	--output	output file to which Swagger JSON will be written
-m	--method	specify HTTP verb - GET, POST on which endpoint URL will be invoked
-h	--header	specify any request headers that should be sent when endpoint URL is invoked
-p	--param	specify request param in key value params e.g: param=value, you can specify multiple -p arguments
-pp	--pathparam	specify path parameter values part of endpoint URL, path parameters should be specified in endpoint as "{pathParameterName}" and its value specified using this argument. You can specify multiple path parameters. please refer examples section for more details.
-a	--authentication	Acts as a boolean command line arguments specifying whether authentication is required for invoking endpoint URL
-username	--username	Username for authentication
-password	--password	Password for authentication
-host	--host	Hostname value will be populated in Swagger JSON's 'host' attribute
-apipath	--apipath	Base Path for Swagger document
-apiname	--apiname	Unique API name for a given endpoint URL
-apidescription	--apidescription	API Description for a given endpoint URL
-apisummary	--apisummary	Summary for given endpoint URL
-tag	--apiTag	Tag name for given endpoint URL. You can provide multiple tag names for the endpoint
-basepath	--basepath	Base Path for Swagger JSON's 'basepath' attribute, Swagger API path is calculated from base path
-help	--help	Display help

CLI Examples

GET API without any parameters and authentication:

<JAVA_HOME>/bin/java" -jar %JAR% -e "http://httpbin.org/ip" -o "SWAGGER-DOC-FILE-PATH" -m "GET" -apiname "UniqueApiName" -tag "GetIPAddress" -apiSummary "API to fetch IP Address" -apidescription "Fetch IP address in origin attribute"

GET API with authentication using -a, --username and --password:

<JAVA_HOME>/bin/java" -jar %JAR% -e "http://httpbin.org/ip" -o "SWAGGER-DOC-FILE-PATH" -m "GET" -a --username "someusername" --password "somePassword" -apiname "UniqueApiName" -tag "GetIPAddress" -apisummary "API to fetch IP Address" -apidescription "Fetch IP address in origin attribute"

GET API with query parameters using -p argument:

<JAVA_HOME>/bin/java" -jar %JAR% -e "http://httpbin.org/ip" -o "SWAGGER-DOC-FILE-PATH" -m "GET" -a --username "someusername" --password "somePassword" -p "param1=value1" -p "param2=value2" -apiname "UniqueApiName" -tag "GetIPAddress" -apisummary "API to fetch IP Address" -apidescription "Fetch IP address in origin attribute"

GET API with path parameters using -pp argument:

<JAVA_HOME>/bin/java" -jar %JAR% -e "http://httpbin.org/ip/{pathparam1}/{pathparam2}" -o "SWAGGER-DOC-FILE-PATH" -m "GET" -a --username "someusername" --password "somePassword" -pp "pathparam1=value1" -pp "pathparam2=value2" -apiname "UniqueApiName" -tag "GetIPAddress" -apisummary "API to fetch IP Address" -apidescription "Fetch IP address in origin attribute"

GET API with path parameters using -pp argument and query parameters using -p:

<JAVA_HOME>/bin/java" -jar %JAR% -e "http://httpbin.org/ip/{pathparam1}/{pathparam2}" -o "SWAGGER-DOC-FILE-PATH" -m "GET" -a --username "someusername" --password "somePassword" -pp "pathparam1=value1" -pp "pathparam2=value2" -p "queryparam=value" -apiname "UniqueApiName" -tag "GetIPAddress" -apisummary "API to fetch IP Address" -apidescription "Fetch IP address in origin attribute"

POST API with path parameters using -pp argument and query parameters using -p:

<JAVA_HOME>/bin/java" -jar %JAR% -e "http://httpbin.org/ip/{pathparam1}/{pathparam2}" -o "SWAGGER-DOC-FILE-PATH" -m "POST" -a --username "someusername" --password "somePassword" -pp "pathparam1=value1" -pp "pathparam2=value2" -p "queryparam=value" -apiname "UniqueApiName" -tag "GetIPAddress" -apisummary "API to fetch IP Address" -apidescription "Fetch IP address in origin attribute"

DELETE API with parameters:

<JAVA_HOME>/bin/java" -jar %JAR% -e "http://httpbin.org/ip/{pathparam1}/{pathparam2}" -o "SWAGGER-DOC-FILE-PATH" -m "DELETE" -a --username "someusername" --password "somePassword" -pp "pathparam1=value1" -pp "pathparam2=value2" -p "queryparam=value" -apiname "UniqueApiName" -tag "GetIPAddress" -apisummary "API to fetch IP Address" -apidescription "Fetch IP address in origin attribute"

Swagger Model generation using APIs

You can use SwaggerGenerator class for generating Swagger JSON, just pass SwaggerGeneratorInput to generator class..voila it will generate Swagger model for you!

Example for generating Swagger Model using API

SwaggerGeneratorInput userInput = new SwaggerGeneratorInput.Builder()
                                 .endpoint(endpoint)
								 .method(method)
								 .pathParams(pathParamMap)
								 .parameters(paramMap)
								 .headers(headerMap)
								 .swaggerJSONFilePath(outputFilePath)
								 .authentication(isAuthenticationNeeded)
								 .username(username)
								 .password(password)
								 .host(host)
								 .basePath(basePath)
								 .apiName(apiName)
								 .apiDescription(apiDescription)
								 .apiSummary(apiSummary)
								 .apiTags(apiTags)
								 .build();
SwaggerGenerator main = new SwaggerGenerator(userInput);
Optional<Swagger> outputSwagger = main.buildSwaggerJson();
if(outputSwagger.isPresent()){
		//then do something...
}

Development

Want to contribute? Great! Open an issue or email me providing your feedback or open a pull request.

Todos

• Consider JSON request data
• Consider to emit response headers in Swagger JSON document
• Consider to generate Swagger document in XML format
• Fix bugs