Exception due to Zencoder response headers being lower-case now

[OlafZwe]

This most recent zencoder-php SDK throws the following exception as a result of any API requests:
Response header is missing Content-Type

The reason appears to be that the SDK checks for the following response header: Content-Type. A recent change to Zencoder appears to have resulted in all response headers being returned in lower case. So the SDK is not finding the new content-type lower case header and throwing the above exception.

A quick and dirty fix we applied was to use the following code in the Services/Zencoder.php _processResponse($response) function (line 234):

if (empty($headers['Content-Type'])) {
    if (empty($headers['content-type'])) {
        throw new Services_Zencoder_Exception('Response header is missing Content-Type', $body);
    } else {
        $headers['Content-Type'] = $headers['content-type'];
    }
}

[jgreer]

The Zencoder API returns Content-Type using that capitalization. Can you provide an example request (with authentication obscured) where you see that happening?

It might be that you've got a proxy server or library that's altering the headers.

[GC-Mark]

We are seeing exactly the same thing with our integration. Since 3-4 days ago, the response headers are all lowercase so it throws the Services_Zencoder_Exception exception.

We haven't changed anything on our side that I know of that could have affected this.

[GC-Mark]

...having said that, when we run the same code on our local testing servers, the headers used are in the correct Upper/Lower case format

[OlafZwe]

After doing some additional testing, we found that the Zencoder servers indeed return the correct header format (capitalized), by testing on our server with the following command, curl -v -H 'zencoder-api-key: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx' https://app.zencoder.com/api/v2/outputs/2079092822/progress.json:

< HTTP/1.1 200 OK
< Date: Thu, 15 Nov 2018 13:41:54 GMT
< Content-Type: application/json; charset=utf-8
< Content-Length: 20
< Connection: keep-alive
< Server: ZenServer 0.2.0

So the issue does not appear to be a proxy.

However, the curl command used in the zencoder-php library returns lower-case headers. We tested this using the following simplified script:

<?php

$ch = curl_init();
curl_setopt_array($ch, array (
    CURLOPT_URL               => "https://app.zencoder.com/api/v2/outputs/2079092822/progress.json",
    CURLOPT_HTTPGET           => 1,
    CURLOPT_HEADER            => 1,
    CURLOPT_RETURNTRANSFER    => 1,
    CURLOPT_CONNECTTIMEOUT    => 30,
    CURLOPT_TIMEOUT           => 60,
    CURLOPT_SSL_VERIFYPEER    => 1,
    CURLOPT_SSL_VERIFYHOST    => 2,
    CURLOPT_HTTPHEADER        => array (
        "zencoder-api-key: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
    )
));

$result=curl_exec($ch);
print_r($result);
curl_close($ch);

and got the following output (truncated):

HTTP/2 200
date: Thu, 15 Nov 2018 13:53:28 GMT
content-type: application/json; charset=utf-8
content-length: 20
server: ZenServer 0.2.0
...

(note the lower-case headers)

We suspect this might be a problem with a specific PHP and/or curl version, so here are the PHP and curl versions:

php --version
PHP 7.1.24

curl_version();
[version_number] => 474624
[age] => 4
[features] => 11518877
[ssl_version_number] => 0
[version] => 7.62.0
[host] => x86_64-redhat-linux-gnu
[ssl_version] => OpenSSL/1.0.2p
[libz_version] => 1.2.3

Is there a specific PHP 7 version (or curl version) which zencoder-php is verified on, so we can update to that version?

[jgreer]

Looking at this further, the PHP version is using HTTP 2 instead of 1.1, and the HTTP 2 specification requires that headers are lower-cased. So that seems to be what's causing the difference.

https://httpwg.org/specs/rfc7540.html#HttpHeaders - "Just as in HTTP/1.x, header field names are strings of ASCII characters that are compared in a case-insensitive fashion. However, header field names MUST be converted to lowercase prior to their encoding in HTTP/2. A request or response containing uppercase header field names MUST be treated as malformed (Section 8.1.2.6)."

This library obviously predates HTTP/2 so that wasn't a consideration in the original implementation. But hopefully we can push an update sometime soon that compares in case-insensitive fashion. In the meantime, it looks like the code in this issue is a functional workaround.

[slengyel-lnx]

Same issue here with the lowercased header values using PHP 7.2. Would be great to have an updated version which addresses this bug.

[glensc]

@OlafZwe I've submitted your change as Pull Request: #33

I think it's rather related to curl than PHP version, as I have PHP 5.3 and recent curl, and have lowercased headers in the response.

# curl --version
curl 7.65.0 (x86_64-pld-linux-gnu) libcurl/7.65.0 OpenSSL/1.1.1c zlib/1.2.11 brotli/1.0.7 c-ares/1.14.0 libidn2/2.2.0 libpsl/0.21.0 (+libidn2/2.1.1) libssh2/1.8.2 nghttp2/1.38.0 librtmp/2.3
Release-Date: 2019-05-22
Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtmp rtsp scp sftp smb smbs smtp smtps telnet tftp
Features: AsynchDNS brotli GSS-API HTTP2 HTTPS-proxy IDN IPv6 Kerberos Largefile libz Metalink NTLM NTLM_WB PSL SPNEGO SSL TLS-SRP UnixSockets

@zencoder: could somebody make a patch release?

[jgreer]

Fixed in #34