[typescript-angular2] Arrays in query params not using preferred format

[RichiWIP]

Description

I am currently developing a middleware API and I generate my angular2 client using codegen. I have one call that expects a short array of strings as a query parameter. The current generator will create a call like this:
http://www.foo.bar/somthing?array=value1,value2,value3

My middleware doesn't understand this format and as far as I have researched, it is preferred to use the following format:
http://www.foo.bar/somthing?array=value1&array=value2&array=value3

Swagger-codegen version

2.0.17

Suggest a Fix

I suggest replacing the current template for queryParams with this code:

{{#queryParams}}
        if ({{paramName}} !== undefined) {
            {{#isListContainer}}
                if({{paramName}}){
                    {{paramName}}.forEach((element) => {
                        queryParameters.append('{{baseName}}', <any>element);
                    })
                }
            {{/isListContainer}}
            {{^isListContainer}}
                queryParameters.set('{{baseName}}', <any>{{paramName}});
            {{/isListContainer}}
        }
{{/queryParams}}

[wing328]

The collectionFormat attribute in the OpenAPI/Swagger 2.0 spec is related to the issue you reported.

Your solution will work for your scenario (collectionFormat=multi) but not other valid collectionFormat.

Would you have time to contribute a solution that works with all supported collection formats?

[RichiWIP]

Ah, yes, I see the Problem. A better solution for now would be

{{#queryParams}}
        if ({{paramName}} !== undefined) {
            {{#isCollectionFormatMulti}}
                if({{paramName}}){
                    {{paramName}}.forEach((element) => {
                        queryParameters.append('{{baseName}}', <any>element);
                    })
                }
            {{/isCollectionFormatMulti}}
            {{^isCollectionFormatMulti}}
                queryParameters.set('{{baseName}}', <any>{{paramName}});
            {{/isCollectionFormatMulti}}
        }
{{/queryParams}}

That will at least support "multi" and "csv" (as ts / js will serialize the array as csv). I will give it a try to add support for the other formats and also add this to other param types where allowed.

[wing328]

@RichiWIP thanks. For PHP, we use a function to handle different collection format:

swagger-codegen/samples/client/petstore/php/SwaggerClient-php/lib/ObjectSerializer.php

Lines 173 to 205 in 1ea9865

	/**
	* Serialize an array to a string.
	*
	* @param array $collection collection to serialize to a string
	* @param string $collectionFormat the format use for serialization (csv,
	* ssv, tsv, pipes, multi)
	* @param bool $allowCollectionFormatMulti allow collection format to be a multidimensional array
	*
	* @return string
	*/
	public function serializeCollection(array $collection, $collectionFormat, $allowCollectionFormatMulti = false)
	{
	if ($allowCollectionFormatMulti && ('multi' === $collectionFormat)) {
	// http_build_query() almost does the job for us. We just
	// need to fix the result of multidimensional arrays.
	return preg_replace('/%5B[0-9]+%5D=/', '=', http_build_query($collection, '', '&'));
	}
	switch ($collectionFormat) {
	case 'pipes':
	return implode('|', $collection);
	case 'tsv':
	return implode("\t", $collection);
	case 'ssv':
	return implode(' ', $collection);
	case 'csv':
	// Deliberate fall through. CSV is default format.
	default:
	return implode(',', $collection);
	}
	}

and use the collectionFormat mustache tag to access the collectionFormat value in the template:

https://github.com/swagger-api/swagger-codegen/blob/master/modules/swagger-codegen/src/main/resources/php/api.mustache#L180-L184

[RichiWIP]

I created a gist with my proposal for the template changes. I have added the proper serialization for the different collection formats to query params, form params and header params (here without multi as it is not supported).
I have also added a constant array of all APIS to apis.mustache to make it easier to import libraries with a great number of api classes. That is the only change to apis.mustache, it is not required for the actual implementation of collection formats.

https://gist.github.com/RichiWIP/8bd23661a4af9629f4c47eb8ab8d25ad

[wing328]

@RichiWIP looks good. Please file a PR so that we can review the change more easily.

[wing328]

Closed via #4539

Thanks @RichiWIP for the enhancement.