CODEWITHSUNDEEP
c#.netresthttpdotnet-httpclient
Prabhu
Prabhu

Reputation: 13335

How to clone a HttpRequestMessage when the original request has Content?

I'm trying to clone a request using the method outlined in this answer: https://stackoverflow.com/a/18014515/406322

However, I get an ObjectDisposedException, if the original request has content.

How can you reliably clone a HttpRequestMessage?

Upvotes: 31

Views: 26123

Answers (3)

Amichai
Amichai

Reputation: 374

Carlos's answer with some linq shortcuts:

public static async Task<HttpRequestMessage> Clone(this HttpRequestMessage httpRequestMessage)
{
    HttpRequestMessage httpRequestMessageClone = new HttpRequestMessage(httpRequestMessage.Method, httpRequestMessage.RequestUri);

    if (httpRequestMessage.Content != null)
    {
        var ms = new MemoryStream();
        await httpRequestMessage.Content.CopyToAsync(ms);
        ms.Position = 0;
        httpRequestMessageClone.Content = new StreamContent(ms);

        httpRequestMessage.Content.Headers?.ToList().ForEach(header => httpRequestMessageClone.Content.Headers.Add(header.Key, header.Value));
    }

    httpRequestMessageClone.Version = httpRequestMessage.Version;

    httpRequestMessage.Properties.ToList().ForEach(props => httpRequestMessageClone.Properties.Add(props));
    httpRequestMessage.Headers.ToList().ForEach(header => httpRequestMessageClone.Headers.TryAddWithoutValidation(header.Key, header.Value));

    return httpRequestMessageClone;
}

UPDATED VERSION FOR .NET VERSION > .NET 5

public static async Task<HttpRequestMessage> Clone(this HttpRequestMessage request)
{
    var clone = new HttpRequestMessage(request.Method, request.RequestUri)
    {
        Version = request.Version
    };

    if (request.Content != null)
    {
        var ms = new MemoryStream();
        await request.Content.CopyToAsync(ms);
        ms.Position = 0;
        clone.Content = new StreamContent(ms);

        request.Content.Headers.ToList().ForEach(header => clone.Content.Headers.TryAddWithoutValidation(header.Key, header.Value));
    }

    request.Options.ForEach(option => clone.Options.TryAdd(option.Key, option.Value));
    request.Headers
        .ForEach(header => clone.Headers.TryAddWithoutValidation(header.Key, header.Value));

    return clone;
}

Upvotes: 4

Carlos P
Carlos P

Reputation: 3989

This should do the trick:

    public static async Task<HttpRequestMessage> CloneHttpRequestMessageAsync(HttpRequestMessage req)
    {
        HttpRequestMessage clone = new HttpRequestMessage(req.Method, req.RequestUri);

        // Copy the request's content (via a MemoryStream) into the cloned object
        var ms = new MemoryStream();
        if (req.Content != null)
        {
            await req.Content.CopyToAsync(ms).ConfigureAwait(false);
            ms.Position = 0;
            clone.Content = new StreamContent(ms);

            // Copy the content headers
            foreach (var h in req.Content.Headers)
                clone.Content.Headers.Add(h.Key, h.Value);
        }


        clone.Version = req.Version;

        foreach (KeyValuePair<string, object?> option in req.Options)
            clone.Options.Set(new HttpRequestOptionsKey<object?>(option.Key), option.Value);

        foreach (KeyValuePair<string, IEnumerable<string>> header in req.Headers)
            clone.Headers.TryAddWithoutValidation(header.Key, header.Value);

        return clone;
    }

Upvotes: 50

Darrel Miller
Darrel Miller

Reputation: 142222

If you call LoadIntoBufferAsync on the content, you can guarantee that the content is buffered inside the HttpContent object. The only problem remaining is that reading the stream does not reset the position, so you need to ReadAsStreamAsync and set the stream Position = 0.

My example is very similar to the one Carlos showed...

 private async Task<HttpResponseMessage> CloneResponseAsync(HttpResponseMessage response)
        {
            var newResponse = new HttpResponseMessage(response.StatusCode);
            var ms = new MemoryStream();

            foreach (var v in response.Headers) newResponse.Headers.TryAddWithoutValidation(v.Key, v.Value);
            if (response.Content != null)
            {
                await response.Content.CopyToAsync(ms).ConfigureAwait(false);
                ms.Position = 0;
                newResponse.Content = new StreamContent(ms);

                foreach (var v in response.Content.Headers) newResponse.Content.Headers.TryAddWithoutValidation(v.Key, v.Value);

            }
            return newResponse;
        }

```

Upvotes: 8

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