1 Minute Fixes - Handling 302 Redirect urls

[wyattdave]

Power Automate does not handle 302 redirects out of the box like other web clients do.

A 302 redirect is when an API replies with a url that it expects you to then follow. A 301 is a permanent redirect (e.g change or url when rebranded) and a 302 is temporary (often for security).

The only way I have seen to handle it is to catch the exception and then use the redirect url in a new http call (the url is normally returned in the Location header). 

But this is not great if you want to scale out the connection (and let's be honest it's a little janky). To do it properly we need a custom connector, but guess what, they don't handle them either. Luckily there is a way, and thats so use some custom code.

The code will automatically follow the redirect url and pass on the response.

public class Script : ScriptBase
{
  public override async Task<HttpResponseMessage> ExecuteAsync()
{
    // Use the context to forward/send an HTTP request
    HttpResponseMessage response = await this.Context.SendAsync(this.Context.Request, this.CancellationToken).ConfigureAwait(false);
    // Check if the response is a 302 redirect
    if (response.StatusCode == HttpStatusCode.Found)
    {
        // If has Loocation Header extract the redirect URL from the Location header
        if (response.Headers.Location != null)
        {
            var redirectUrl = response.Headers.Location.ToString();     
            // Create a new request with the redirect URL
            var redirectRequest = new HttpRequestMessage(HttpMethod.Get, redirectUrl);
            // Forward the new request to the redirect URL
            response = await this.Context.SendAsync(redirectRequest, this.CancellationToken).ConfigureAwait(true);
        }
        else
        {
            // If the Location header is not present, return an error response
            response = new HttpResponseMessage(HttpStatusCode.BadRequest);
            response.Content = CreateJsonContent("Location header missing in the redirect response.");
        }
    }
    else if (response.IsSuccessStatusCode)
    {
        // If the response is successful, perform any necessary transformations
        var responseString = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
        // Example case: response string is some JSON object
        var result = JObject.Parse(responseString);  
        // Wrap the original JSON object into a new JSON object with just one key ('wrapped')
        var newResult = new JObject
        {
            ["wrapped"] = result,
        };    
        response.Content = CreateJsonContent(newResult.ToString());
    }
    return response;
}
}

And that's it, it should work on any api and means your custom connector will act like one api call and not need exception handling.

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This is a series of short blogs designed to help find solutions for random problems before you ask, keep your eyes out for more

l also do long form and broader Power Platform blogs here https://dev.to/wyattdave