Support downloading feeds with HTTP basic authentication

[barbeau]

Summary:

I requested an API key for Metra in Chicago as part of CUTR-at-USF/transit-feed-quality-calculator#29, and I found out that they use HTTP basic authentication for access credentials - they gave me a username and password.

Currently, we only support a URL, which can include an API key embedded in the URL as an HTTP request parameter. However, basic authentication is accomplished via setting the header, which we currently don't support.

So, we should add an option for HTTP basic authentication via a username and password.

Here's a Java example:
https://stackoverflow.com/a/7020054/937715

Here is their developer site (which as far as I can tell doesn't document this anywhere - I had to ask via email):
https://metrarail.com/developers

Here is the sample code they gave me:

// Example with C# with WebRequest:
var webRequest = WebRequest.Create(uri);
webRequest.Credentials = new NetworkCredential("userName", "password");
using (var webResponse = webRequest.GetResponse())
{
    using (var responseStream = webResponse.GetResponseStream())
    {
        return new StreamReader(responseStream).ReadToEnd();
    }
}
 
 
 
// Example with PHP using CURL:
$login = 'login';
$password = 'password';
$url = 'http://your.url';
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL,$url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
curl_setopt($ch, CURLOPT_USERPWD, "$login:$password");
$result = curl_exec($ch);
curl_close($ch);  
echo($result);

Steps to reproduce:

1. Try to download Metra's feeds via web interface or batch downloader:

Host
https://gtfsapi.metrarail.com

Raw GTFS Feeds
• GET - /gtfs/raw/positionUpdates.dat
• GET - /gtfs/raw/tripUpdates.dat
• GET - /gtfs/raw/alerts.dat
• GET - /gtfs/raw/schedule.zip

JSON GTFS Feeds
• /gtfs/alerts
• /gtfs/positions
• /gtfs/tripUpdates

Additional API Information
https://metrarail.com/developers/metra-gtfs-api

Expected behavior:

Give me a way to download the feeds using a username and password

Observed behavior:

You can't download feeds if the server requires a username and password via HTTP basic authentication

Platform:

N/A