API OK MediaPost problem with symbols +, &, #, %?

Question

Classmates

I write symbols in the request body, and it gives errors
{"error_code":3,"error_msg":"METHOD : Method can not be null","error_data":null}
{"error_code":104,"error_msg":"PARAM_SIGNATURE : Invalid signature feecb27fe2c3422aed4d5967f0b5d7e3, calculated by string application_key=CBAKAMHLEBABABABAattachment={ \"media\": [ { \"type\": \"text\", \"text\": \" in Prague, only with official documents. Cooking for the head chef, for the menu - not only helped, but also cooked more fully. Dosvid є obov'yazkovim. Payment 120 Korun/year. B0 607 407 092, [email protected]\" } ]}format=jsongid=53327505719498method=mediatopic.

Answer 1

are you encrypting the signature with an MD5 hash?
the request body uses attachment, before sending, all attachment characters must be encoded in url format
on php
on js
in c#
where attachment - your attachment before encoding
encode_attachment - attachment after encoding in url
and encode_attachment already sent to MediaPost
in c# looks like this (works)

h0 = "application_key=" + OK.APPK + "attachment=" + attachments + "format=jsongid=" + gid + "method=mediatopic.posttype=GROUP_THEME" + OK.SSK;
                g = GetMD5Hash(string.Format("{0}", h0));
                attachments = HttpUtility.UrlEncode(attachments);
                request_path = "https://api.ok.ru/fb.do?application_key=" + OK.APPK + "&attachment=" + attachments + "&format=json&gid=" + gid + "&method=mediatopic.post&type=GROUP_THEME&sig=" + g + "&access_token=" + OK.AccessToken;
                string req = Response(request_path, sender);

ps in the signature, you need to use attachment before encoding, and in the request itself, attachment is encoded
p.s.s. there are some encoders (for example, in C#...) that do not process all characters
. MD5
for js ( poke )
for php $hash = md5($str);
for c#

public static string GetMD5Hash(string input)
        {
             var x = new System.Security.Cryptography.MD5CryptoServiceProvider();
             var bs = Encoding.UTF8.GetBytes(input);
             bs = x.ComputeHash(bs);
             var s = new StringBuilder();
             foreach (var b in bs)
             {
                s.Append(b.ToString("x2").ToLower());
             }
             return s.ToString();
        }