How to read only a specific part from HTTP Response body

Question

I need to read only the mode segment from the below response body.

grant_type=password&username=demouser&password=test123&client_id=500DWCSFS-D3C0-4135-A188-17894BABBCCF&mode=device

I used the below function to read the HTTP body and it gives me the entire body. How to chop the mode segment without using substring or changing the value in seek() : bodyStream.BaseStream.Seek(3, SeekOrigin.Begin);

var bodyStream = new StreamReader(HttpContext.Current.Request.InputStream);
bodyStream.BaseStream.Seek(0, SeekOrigin.Begin);
var bodyText = bodyStream.ReadToEnd();

@SimonH. ReadBlock() also requests parameter to specify a start index. wont be able to specify an index because index might change based on the length of the username and password — Harsha W, Mar 08 '18 at 07:55

score 2 · Accepted Answer · answered Mar 08 '18 at 07:57

You can't. HTTP uses TCP, which requires you to read the entire body anyway, you can't "seek" into a TCP stream. Well, you can, but that still reads the entire body and discards the unused pieces.

So you have to read the entire stream, and you have to meaningfully parse it, because another parameter could also contain the string "mode", and it could also be at the start, so you also can't search for &mode.

Given this is a form post, you can simply access Request.Form["mode"]. If you do want to parse it yourself:

string formData;
using (reader = new StreamReader(HttpContext.Current.Request.InputStream))
{
    formData = reader.ReadToEnd();
}

var queryString = HttpUtility.ParseQueryString(formData);
var mode = queryString["mode"];

Thanks @CodeCaster. This is what I want. +1 – Harsha W Mar 08 '18 at 08:02 — Harsha W, Mar 08 '18 at 08:02

How to read only a specific part from HTTP Response body

1 Answers1