How to pass API endpoint URL containing \ to

Question

I'm trying to pass the given URL to the setEndpoint method, but I'm getting an error.

This particular API URL contains backslash and maybe that's the problem because the code works fine with other URLs which don't have backslashes.

Please let me know how do we encode/decode this to pass it as an argument.

 HttpRequest req = new HttpRequest();

 String url='https://api.example.com/s1/output?filter\[abc\]\[\]=xyz';

 req.setEndpoint(url);

Also, this URL works completely fine with the curl command!

Answer 1

I strongly suspect that something is going sideways because you're not properly escaping the non-safe URL characters (like \ and [); in a URL, they must be in a certain style known as "percent encoding". Here's how I'd approach your problem:

ApexPages.PageReference ref = new ApexPages.PageReference('https://api.example.com/output');
ref.getParameters().put('filter\\[abc\\]\\[\\]', 'xyz');
String theUrl = ref.getUrl();
req.setEndpoint(theUrl);

This produces output like:

https://api.example.com/output?filter%5C%5Babc%5C%5D%5C%5B%5C%5D=xyz

Things like "curl" are smart enough to do this for you, but in Salesforce, you always need to use either EncodingUtils.urlEncode or PageReference.

Edit: The URL doesn't have backslashes in it; the backslashes that were used are required by the shell for curl to properly detect the brackets. So, simply removing those should fix the issue:

ApexPages.PageReference ref = new ApexPages.PageReference('https://api.example.com/output');
ref.getParameters().put('filter[abc][]', 'xyz');
String theUrl = ref.getUrl();
req.setEndpoint(theUrl);