How to add alt text for image uploads?

[mbourne]

Image uploading is working fine, but I want to alt text.

I tried my luck (since this is the Twitter API's syntax) with adding 'alt_text' => 'My alt text here' as in the following block, but it fell over, and didn't post the tweet at all.

$media = $connection->upload('media/upload', ['media' => 'path/to/image']);
$parameters = [
	'status' => 'My status here',
	'media_ids' => $media->media_id_string,
	'alt_text' => "My alt text here"
];
$connection->post('statuses/update', $parameters);

How do I add alt text? TIA.

[abraham]

You should set the alt text with POST media/metadata/create. It will require three API calls.

1. Upload media
2. Add metadata to the media
3. Create tweet with media

[mbourne]

Thank you for your response. I'm no OOP programmer, but I tried.

I added the following functions to TwitterOAuth.php:

    public function uploadMeta($path, array $parameters = [])
    {
        return $this->postMetadata($path, $parameters);
    }

and

    private function postMetadata($path, array $parameters)
    {		
        return $this->http('POST', self::UPLOAD_HOST, $path, $parameters, false);
    }

I'm calling it like this:

$result1 = $media = $connection->upload('media/upload', ['media' => "path/to/img"]);
				
$parameters = [
	'alt_text' => 'alt text here',
	'media_id' => $media->media_id_string
];

$result2 = $connection->uploadMeta('media/metadata/create', $parameters);
				
$parameters = [
	'status' => $status,
	'media_ids' => $media->media_id_string
];

$result3 = $connection->post('statuses/update', $parameters);

$result2 is giving me

  public 'request' => string '/1.1/media/metadata/create.json' (length=31)
  public 'error' => string 'Invalid json payload.' (length=21)

I tried to json_encode the $parameters array, but that was a folly.

The $parameters array within my postMetadata function is correctly (I presume) showing as Array ( [alt_text] => Correct_alt_text_here [media_id] => correct_image_ID_here )

The image upload and the status post worked fine, but of course, the alt-text did not.

So it appears I'm close.

What am I missing? TIA.

[mbourne]

I'm still trying on this and noticed an error I was making. I'm now defining $parameters as

$parameters['media_id'] = "media ID here as string";
$parameters['alt_text']['text'] = $meta;

When I json_encode this to check if it looks right, it produces:

{
"media_id":"correct media id as string here",
"alt_text":
  {
     "text":"Correct alt text here"
  }
}

This is the same format as given on https://developer.twitter.com/en/docs/twitter-api/v1/media/upload-media/api-reference/post-media-metadata-create

So it appears the $parameter array I'm passing is correctly set up, yet I'm still getting public 'error' => string 'Invalid json payload.' and it's not posting.

Can anyone see the problem?

[junaidshad]

Hey, Did you manage to add Alt-texts to the uploading media ?

[mbourne]

I only managed to get it to add a empty alt tag. I think I got busy on other things and never managed to solve it.

[junaidshad]

I followed this thread and it helped: #456

$twitter->post('media/metadata/create', $alt_text_payload, true);

According to the thread, passing true parameter sets the content-type to json.

[abraham]

$connection = new TwitterOAuth(...);

$media_payload = [
    'media' => __DIR__ . '/tests/kitten.jpg',
];
$response = $connection->upload('media/upload', $media_payload);

$metadata_payload = [
    'media_id' => $response->media_id_string,
    'alt_text' => [
        'text' => 'Good kitty',
    ],
];
$connection->post('media/metadata/create', $metadata_payload, true);

var_dump($connection->getLastHttpCode());
$status_payload = [
    'status' => 'Hello World ' . time(),
    'media_ids' => $response->media_id_string,
];
$response = $connection->post('statuses/update', $status_payload);

var_dump($response);