How to clone a HttpRequestMessage when the origina

问题:

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?

回答1:

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
            if (req.Content.Headers != null)
                foreach (var h in req.Content.Headers)
                    clone.Content.Headers.Add(h.Key, h.Value);
        }


        clone.Version = req.Version;

        foreach (KeyValuePair<string, object> prop in req.Properties)
            clone.Properties.Add(prop);

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

        return clone;
    }

回答2:

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;
        }

```