how to generate URI parameter for dynamic feign basePath using swagger codegen?

Question

I have a pretty simple question :)

According to feign documents, they are supporting in changing the basePath of a feign client object dynamically by passing URI parameter trough the api function like so:

GOOD Example:

interface MyClient {
    @RequestLine("GET /internal-service")
    String internalService(URI baseUrl);
}

The thing is I'm using swagger, who generates my API from a yaml file and adding @Param annotation to all function parameters, which is not good for me.

BAD Example:

interface MyClient {
    @RequestLine("GET {baseUrl}/internal-service")
    String internalService(@Param("baseUrl") String host);
}

Is there a way to make swagger generator to generate an API with a URI param, without the @Param annotation?

Desired Outcome Example:

interface MyClient {
    @RequestLine("POST /internal-service")
    String internalService(URI baseUrl, @Param("someParam") String someParam);
}

Answer 1

Initial solution:

After some investigation I came to realize that there is no support in swagger-codegen 2.2.3 for generating URI parameter as part of the client API function.

But there is an option in swagger-codegen-maven-plugin configuration of "templateDirectory - directory with mustache templates", for giving a path to a folder including mustache templates, which will take the templates in that folder and override the existing with the same name.

example:

        <plugin>
            <groupId>io.swagger</groupId>
            <artifactId>swagger-codegen-maven-plugin</artifactId>
            <executions>
                <execution>
                    <id>my-project-api-client-kit</id>
                    <goals>
                        <goal>generate</goal>
                    </goals>
                    <configuration>
                        <inputSpec>${project.build.directory}/my-project-api.yaml</inputSpec>
                        <language>java</language>
                        <configOptions>
                            <dateLibrary>java8</dateLibrary>
                            <sourceFolder>src/main/java</sourceFolder>
                        </configOptions>
                        <modelPackage>my.project.ck.resources.models</modelPackage>
                        <apiPackage>my.project.ck.resources.interfaces</apiPackage>
                        <library>feign</library>
                        <templateDirectory>/myTemplateFolder/</templateDirectory>
                    </configuration>
                </execution>
            </executions>
        </plugin>

And inside the custom templates folder, put your own api.mustache file with the additional "URI basePath" parameter:

...
{{#returnType}}{{{returnType}}} {{/returnType}}{{^returnType}}void {{/returnType}}{{nickname}}(URI basePath, {{#allParams}}{{^isBodyParam}}{{^legacyDates}}@Param("{{paramName}}") {{/legacyDates}}{{#legacyDates}}@Param(value="{{paramName}}", expander=ParamExpander.class) {{/legacyDates}}{{/isBodyParam}}{{{dataType}}} {{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}});
...

Note: Swagger provides a lot of templates for a variety of uses, make sure to take and modify the correct api.mustache template file according to which you are using. in the above example I modified (and override) the java.libraries.feign/api.mustache file because this is the file my plugin is configured too (as in the example).