腾讯云v3签名的使用

本文的目标是：用“签名方法 v3”调用“录音文件识别请求”接口

v3文档中提供了各大编程语言的演示代码，选择合适自己的。

其它接口的文档写得挺好懂的，示例代码复制过来就能用，

就这个v3的文档，我感觉写不太明白，首次接触真的很懵逼！

现在自己调用成功了特此来记录下。

一、修改公共参数：

v3中有这么几个参数：

对应以下画圈圈的做修改：

所以得到修改后的代码：

string service = "asr";
string endpoint = "asr.tencentcloudapi.com";
string region = "";
string action = "CreateRecTask";
string version = "2019-06-14";

二、修改提交参数

v3中有这么一个变量（就是你要提交的参数的json格式）：

string requestPayload = "{"Limit": 1, "Filters": [{"Values": ["\u672a\u547d\u540d"], "Name": "instance-name"}]}";

修改为目标接口的参数（按需提供、去掉公共参数）：

StringBuilder parameter = new StringBuilder();
parameter.Append("{");
parameter.Append(""EngineModelType":"16k_zh",");
parameter.Append(""ChannelNum":1,");
parameter.Append(""SourceType":1,");
parameter.Append(""Data":"base64",");
parameter.Append(""ResTextFormat":1,");
parameter.Append(""FilterPunc":2");
parameter.Append("}");
string requestPayload = parameter.ToString();

三、发送请求

到这一步就OK了：

var headers = Application.BuildHeaders(SECRET_ID, SECRET_KEY, service
    , endpoint, region, action, version, DateTime.UtcNow, requestPayload);

HttpWebRequest request = (HttpWebRequest)WebRequest.Create($"https://{endpoint}");
request.Method = "post";

foreach (KeyValuePair<string, string> kv in headers)
{
    request.Headers.Add(kv.Key, kv.Value);
}

byte[] byteData = Encoding.UTF8.GetBytes(requestPayload);
request.ContentLength = byteData.Length;

using (Stream postStream = request.GetRequestStream())
{
    postStream.Write(byteData, 0, byteData.Length);
}

WebResponse response = request.GetResponse();
StreamReader reader = new StreamReader(response.GetResponseStream());
string result = reader.ReadToEnd();

response.Close();
reader.Dispose();

最后贴出完整代码：

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Security.Cryptography;
using System.Text;

namespace ConsoleDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            // 填入你自己的密钥参数
            string SECRET_ID = "";
            string SECRET_KEY = "";

            string service = "asr";
            string endpoint = "asr.tencentcloudapi.com";
            string region = "";
            string action = "CreateRecTask";
            string version = "2019-06-14";

            StringBuilder parameter = new StringBuilder();
            parameter.Append("{");
            parameter.Append(""EngineModelType":"16k_zh",");
            parameter.Append(""ChannelNum":1,");
            parameter.Append(""SourceType":1,");
            parameter.Append(""Data":"base64",");
            parameter.Append(""ResTextFormat":1,");
            parameter.Append(""FilterPunc":2");
            parameter.Append("}");
            string requestPayload = parameter.ToString();

            var headers = Application.BuildHeaders(SECRET_ID, SECRET_KEY, service
                , endpoint, region, action, version, DateTime.UtcNow, requestPayload);

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create($"https://{endpoint}");
            request.Method = "post";

            foreach (KeyValuePair<string, string> kv in headers)
            {
                request.Headers.Add(kv.Key, kv.Value);
            }

            byte[] byteData = Encoding.UTF8.GetBytes(requestPayload);
            request.ContentLength = byteData.Length;

            using (Stream postStream = request.GetRequestStream())
            {
                postStream.Write(byteData, 0, byteData.Length);
            }

            WebResponse response = request.GetResponse();
            StreamReader reader = new StreamReader(response.GetResponseStream());
            string result = reader.ReadToEnd();

            response.Close();
            reader.Dispose();
        }
    }

    public class Application
    {
        public static string SHA256Hex(string s)
        {
            using (SHA256 algo = SHA256.Create())
            {
                byte[] hashbytes = algo.ComputeHash(Encoding.UTF8.GetBytes(s));
                StringBuilder builder = new StringBuilder();
                for (int i = 0; i < hashbytes.Length; ++i)
                {
                    builder.Append(hashbytes[i].ToString("x2"));
                }
                return builder.ToString();
            }
        }

        public static byte[] HmacSHA256(byte[] key, byte[] msg)
        {
            using (HMACSHA256 mac = new HMACSHA256(key))
            {
                return mac.ComputeHash(msg);
            }
        }

        public static Dictionary<String, String> BuildHeaders(string secretid,
            string secretkey, string service, string endpoint, string region,
            string action, string version, DateTime date, string requestPayload)
        {
            string algorithm = "TC3-HMAC-SHA256";
            string datestr = date.ToString("yyyy-MM-dd");
            DateTime startTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
            long requestTimestamp = (long)Math.Round((date - startTime).TotalMilliseconds, MidpointRounding.AwayFromZero) / 1000;

            // ************* 步骤 1：拼接规范请求串 *************
            string httpRequestMethod = "POST";
            string canonicalUri = "/";
            string canonicalQueryString = "";
            string contentType = "application/json";
            string canonicalHeaders = "content-type:" + contentType + "; charset=utf-8
" + "host:" + endpoint + "
";
            string signedHeaders = "content-type;host";
            string hashedRequestPayload = SHA256Hex(requestPayload);
            string canonicalRequest = httpRequestMethod + "
"
                + canonicalUri + "
"
                + canonicalQueryString + "
"
                + canonicalHeaders + "
"
                + signedHeaders + "
"
                + hashedRequestPayload;
            Console.WriteLine(canonicalRequest);
            Console.WriteLine("----------------------------------");

            // ************* 步骤 2：拼接待签名字符串 *************
            string credentialScope = datestr + "/" + service + "/" + "tc3_request";
            string hashedCanonicalRequest = SHA256Hex(canonicalRequest);
            string stringToSign = algorithm + "
" + requestTimestamp.ToString() + "
" + credentialScope + "
" + hashedCanonicalRequest;
            Console.WriteLine(stringToSign);
            Console.WriteLine("----------------------------------");

            // ************* 步骤 3：计算签名 *************
            byte[] tc3SecretKey = Encoding.UTF8.GetBytes("TC3" + secretkey);
            byte[] secretDate = HmacSHA256(tc3SecretKey, Encoding.UTF8.GetBytes(datestr));
            byte[] secretService = HmacSHA256(secretDate, Encoding.UTF8.GetBytes(service));
            byte[] secretSigning = HmacSHA256(secretService, Encoding.UTF8.GetBytes("tc3_request"));
            byte[] signatureBytes = HmacSHA256(secretSigning, Encoding.UTF8.GetBytes(stringToSign));
            string signature = BitConverter.ToString(signatureBytes).Replace("-", "").ToLower();
            Console.WriteLine(signature);
            Console.WriteLine("----------------------------------");

            // ************* 步骤 4：拼接 Authorization *************
            string authorization = algorithm + " "
                + "Credential=" + secretid + "/" + credentialScope + ", "
                + "SignedHeaders=" + signedHeaders + ", "
                + "Signature=" + signature;
            Console.WriteLine(authorization);
            Console.WriteLine("----------------------------------");

            Dictionary<string, string> headers = new Dictionary<string, string>();
            headers.Add("Authorization", authorization);
            headers.Add("Host", endpoint);
            headers.Add("Content-Type", contentType + "; charset=utf-8");
            headers.Add("X-TC-Timestamp", requestTimestamp.ToString());
            headers.Add("X-TC-Version", version);
            headers.Add("X-TC-Action", action);
            headers.Add("X-TC-Region", region);
            return headers;
        }
    }
}