Awesome. :)

Would you mind to change code a bit just to follow calling convention of the rest of the code?

Parameters should have a space to separate from parens.

http_build_query( $params );
preg_replace( '/%5B[0-9]+%5D/simU', '%5B%5D', $query );

Also, it would greatly help future developers if you could extend the "double-encode" comment giving a reason to why it has to do it.

Updated

👍
Thanks!
This fixed my issue when using &filter[cat]=n

Hmm.. however it seems to have broken media uploads. (I will double-check how my client is doing things, but it was working fine with the previous method. )

update: OK. It appears my client is fine. Debugging this method compared to the existing methods shows some double-encoding of spaces in the text.

eg: Let's say I'm uploading a media file with the caption uploaded by kosso

working: existing create_signature_string() method:

caption%3Duploaded%2520by%2520kosso%26oauth_consumer_key%3D...

not working: proposed create_signature_string() method (notice double encoding of percent symbol from %20 spaces)

caption%3Duploaded%252520by%252520kosso%26oauth_consumer_key%3D...

So, I found that adding:

$replaced = preg_replace( '/%25/simU', '%', $replaced );

..seems to fix it for all my requests.

giving:

public function create_signature_string( $params ) {
    $query = http_build_query( $params );
    // http_build_query will attach numeric indices for array values, eg
    // filter[post__not_in][0]=1 instead of filter[post__not_in][]=1.
    //
    // Clients issue requests in the form filter[post__not_in][]=1 so
    // we should compare against that. This regex will strip out
    // the numeric indices.
    //
    // cf. http://php.net/manual/en/function.http-build-query.php
    // cf. http://stackoverflow.com/a/11996686/751089
    $replaced = preg_replace( '/%5B[0-9]+%5D/simU', '%5B%5D', $query );
    // http_build_query has urlencoded the parameters, but our calling function
    // expects a double-encoded return value
    // replace encoded percent symbols. 
    $replaced = preg_replace( '/%25/simU', '%', $replaced );
    return urlencode( $replaced );
}

Thanks @kosso. I'm afraid I'm away this week so can't reply properly - sorry! Don't mind if you want to re-raise with commits of your own.

@rachelbaker, would you be open to a PR adding unit tests to the plugin? Then all could be robust and reliable 🙂

Had a similar issue with the Wordpress Example OAuth Client which uses (an old version... of) https://github.com/thephpleague/oauth1-client/, see this issue about nested arrays.

Just wanted to say that to fix the brackets encoding problem, simply changing class-wp-rest-oauth1.php line 736 to:

$param_key = $key . '[' . $param_key . ']'; // Handle multi-dimensional array

did the trick :)