Support multiple Search returnFields

I've been troubleshooting some gcloud-ruby issues connecting to the Cloud Search API. I've been looking at gcloud-node's implementation, and I can't get find a way to specify multiple returnFields values.

Here is my setup:

$ nodejs
> var gcloud = require('gcloud')(...);
undefined
> var search = gcloud.search();
undefined
> var index = search.index('test');
undefined
> var printSearchResults = function(err, documents) {
...   if (err) {
.....     console.log('there was an error');
.....     console.log(err);
.....   } else {
.....     console.log('the search results were returned:');
.....     console.log(documents);
.....   }
... }
undefined

I can perform a simple search without specifying any returnFields values:

> index.search('ruby', printSearchResults);
undefined
> the search results were returned:
[ { metadata: {},
    baseUrl: '/documents',
    parent: 
     { metadata: {},
       baseUrl: '/indexes',
       parent: [Object],
       id: 'test',
       createMethod: undefined,
       create: undefined,
       delete: undefined,
       exists: undefined,
       get: undefined,
       getMetadata: undefined,
       setMetadata: undefined },
    id: 'gcloud-ruby',
    createMethod: undefined,
    setMetadata: undefined,
    fields: {} } ]

undefined

And I can specify a single returnFields value:

> index.search({query: 'ruby', returnFields: '*'}, printSearchResults);
undefined
> the search results were returned:
[ { metadata: {},
    baseUrl: '/documents',
    parent: 
     { metadata: {},
       baseUrl: '/indexes',
       parent: [Object],
       id: 'test',
       createMethod: undefined,
       create: undefined,
       delete: undefined,
       exists: undefined,
       get: undefined,
       getMetadata: undefined,
       setMetadata: undefined },
    id: 'gcloud-ruby',
    createMethod: undefined,
    setMetadata: undefined,
    fields: { summary: [Object], title: [Object], description: [Object] } } ]

undefined

The trouble I run into is specifying multiple values:

> index.search({query: 'ruby', returnFields: ['title', 'summary', 'description']}, printSearchResults);
undefined
> there was an error
{ errors: undefined,
  code: 400,
  message: 'Invalid JSON payload received. Unknown name "returnFields[1]": Cannot bind query parameter. Field \'returnFields[1]\' could not be found in request message.\nInvalid JSON payload received. Unknown name "returnFields[2]": Cannot bind query parameter. Field \'returnFields[2]\' could not be found in request message.\nInvalid JSON payload received. Unknown name "returnFields[0]": Cannot bind query parameter. Field \'returnFields[0]\' could not be found in request message.',
  response: undefined }

undefined
>

Thanks for the report! I'll get on this 👍

I looked into this a little bit, request uses a module called qs internally, this is a code sample from their docs

Qs.stringify({ a: ['b', 'c', 'd'] });
// 'a[0]=b&a[1]=c&a[2]=d'

This explains the problem we're seeing and it looks like we can get around it by passing request a qsStringifyOptions object with indices set to false. Do we know if that's the standard way the upstream API deals with query strings? Just curious about if it would be safe to turn of indices globally or if we'll need to handle this on a case by case basis.

That's interesting. From the request docs, we can also use useQuerystring: true to use the default querystring module which loses the indices.

But in this case, it looks like the API wants a string and not a list of strings:

...	...	...
`returnFields`	string	List of fields to return in `SearchResult` objects. It can be fields from `Document`, the built-in fields `_rank` and `_score`, and fields defined in `fieldExpressions`. Use `"*"` to return all fields from `Document`.

Looks like there is either a discrepancy in the type or an unknown delimter... subscribed to googleapis/google-cloud-ruby#450 so we can see what needs to be done here when that's resolved.