PHP generates the relevant content of the request signature required by Tencent Cloud COS interface

This article mainly introduces the request signature required to create a COS interface using PHP. It is compared with the examples given in the official documents to verify the correctness of the algorithm. Friends in need can refer to it

What is COS and request signature

COS is the abbreviation and abbreviation of Tencent Cloud Object Storage. The request signature is created by a specific algorithm and needs to be provided by a third party on demand when calling COS related interfaces. A set of string information that will uniquely identify the current third-party identity and provide identification of both communicating parties. Only valid signed COS will provide services

Goal

Use PHP to create the request signature required for the COS interface, compare it with the example given in the official document, and verify the correctness of the algorithm

Understand the request signature

Come first Look at the request signature given in an official document

q-sign-algorithm=sha1&q-ak=[SecretID]&q-sign-time=[SignTime]&q-key-time=[KeyTime ]&q-header-list=[SignedHeaderList]&q-url-param-list=[SignedParameterList]&q-signature=[Signature]

Request signature feature summary

• is a key-value pair format of a string

• key=value, the key is a fixed value

• There are 7 pairs of keys in total =value

• sha1 is also a parameter, but as of the official release, only sha1 is supported, so you can directly assign values ​​to

• SignedHeaderList, SignedParameterList, and Signature. value needs to be generated through an algorithm

For detailed description of key-value pairs, please refer to the official documentation.

Breakdown one by one

Requesting a signature requires a total of 7 values. Let’s explain one by one below and break each one

q-sign-algorithm

Signature algorithm, official Currently only sha1 is supported, so just give the value directly

q-ak

The account ID, which is the user's SecretId, can be obtained on the console Cloud API Key page

q-sign-time

The valid start and end time of the current signature, Unix timestamp format, English half-width semicolon; separated, format such as 1480932292;1481012298

q-key-time

Same as q-sign-time value

q-header-list

Personal understanding, it consists of HTTP request headers, take all or part of the request headers, and change the request in the form of key:value The key part of the item is taken out, converted to lowercase, multiple keys are sorted according to the dictionary, and connected with the characters ; to finally form a string

For example, the original request header has two:

Host: bucket1-1254000000.cos.ap-beijing.myqcloud.com
Content-Type:image/jpeg

key is Host and Content-Type. After operation, content-type;host# is output.

GET /?prefix=abc&max-keys=20

PUT /testfile2 HTTP/1.1

Host: bucket1-1254000000.cos.ap-beijing.myqcloud.com
x-cos-content-sha1: 7b502c3a1f48c8609ae212cdfb639dee39673f5e
x-cos-storage -class: standard

Hello world

PUT /testfile2 HTTP/1.1
Host: bucket1-1254000000.cos.ap-beijing.myqcloud.com
x-cos-content-sha1: 7b502c3a1f48c8609ae212cdfb639dee39673f5e
x-cos-storage -class: standard
Authorization: q-sign-algorithm=sha1&q-ak=AKIDQjz3ltompVjBni5LitkWHFlFpwkn9U5q&> q-sign-time=1417773892;1417853898&q-key-time=1417773892;1417853898&q-header-list =host;x-cos-content -sha1;x-cos-storage-class&q-url-param-list=&q-signature=14e6ebd7955b0c6da532151bf97045e2c5a64e10

Hello world

Conclusion: If the algorithm can get the one after Authorization The string string is correct

Preparation work

Let’s take a look at the (officially provided) user information and HTTP information:

• ##SecretId: AKIDQjz3ltompVjBni5LitkWHFlFpwkn9U5q

• SecretKey: BQYIM75p8x0iWVFSIgqEKwFprpRSVHlz

• Signature valid start time: 1417773892

• Signature valid stop time: 1417853898

• HTTP original request header: According to the example in the previous section, it is not difficult to get that the HTTP original request has three contents: Host, x-cos-content-sha1 and x-cos-storage-class

• HTTP request parameters: Is it a PUT request, no? Parameters

But where did q-signature come from?

As mentioned just now, q-signature also needs to be calculated by a specific algorithm. The following explains how to calculate it

Calculate the request signature

Look at the code first ：

/**
 * 计算签名
 * secretId、secretKey 为必需参数，qSignStart、qSignEnd为调试需要，测试通过后应取消，改为方法内自动创建
 */
function get_authorization( $secretId, $secretKey, $qSignStart, $qSignEnd, $fileUri, $headers ){
 /* 
 * 计算COS签名
 * 2018-05-17
 * author:cinlap <cash216@163>
 * ref:https://cloud.tencent.com/document/product/436/7778
 */

 $qSignTime = "$qSignStart;$qSignEnd"; //unix_timestamp;unix_timestamp
 $qKeyTime = $qSignTime;

 $header_list = get_q_header_list($headers);
 //如果 Uri 中带有 ?的请求参数，该处应为数组排序后的字符串组合
 $url_param_list = &#39;&#39;;

 //compute signature
 $httpMethod = &#39;put&#39;;
 $httpUri = $fileUri;

 //与 q-url-param-list 相同
 $httpParameters = $url_param_list;

 //将自定义请求头分解为 & 连接的字符串
 $headerString = get_http_header_string( $headers );

 // 计算签名中的 signature 部分
 $signTime = $qSignTime;
 $signKey = hash_hmac(&#39;sha1&#39;, $signTime, $secretKey);
 $httpString = "$httpMethod\n$httpUri\n$httpParameters\n$headerString\n";
 $sha1edHttpString = sha1($httpString);
 $stringToSign = "sha1\n$signTime\n$sha1edHttpString\n";
 $signature = hash_hmac(&#39;sha1&#39;, $stringToSign, $signKey);
 //组合结果
 $authorization = "q-sign-algorithm=sha1&q-ak=$secretId&q-sign-time=$qSignTime&q-key-time=$qKeyTime&q-header-list=$header_list&q-url-param-list=$url_param_list&q-signature=$signature";
 return $authorization;
}

For testing, this method should have more parameters than needed. The first six parameters have been given and come from the user, so directly Assign a value to get the following string:

$authorization = "q-sign-algorithm=sha1&q-ak=$secretId&q-sign-time=$qSignTime&q-key-time=$qKeyTime...

$header_list This value must comply with the q-header-list rules and therefore needs to be calculated. The logic is as described above, which is to extract keys from the established request items to form an orderly String, the code is as follows:

/**
 * 按COS要求对header_list内容进行转换
 * 提取所有key
 * 字典排序
 * key转换为小写
 * 多对key=value之间用连接符连接
 * 
 */
function get_q_header_list($headers){
 if(!is_array($headers)){
  return false;
 }

 try{
  $tmpArray = array();
  foreach( $headers as $key=>$value){
   array_push($tmpArray, strtolower($key));
  }
  sort($tmpArray);
  return implode(';', $tmpArray);
 }
 catch(Exception $error){
  return false;
 }
}

$url-param-list As mentioned above, this value is an HTTP request parameter. There is no ? parameter for the PUT method, naturally. The value is empty, so the code is "lazy" and directly gives the empty string.

Signature calculation and things to be careful about

The official has given a complete Algorithm, PHP and even written code, I should be very happy (but! I was dizzy after reading the official document, so I will explain it later), first take a look at the "format" of signature:

SignKey = HMAC-SHA1(SecretKey,"[q-key-time]")
HttpString = [HttpMethod]\n[HttpURI]\n[HttpParameters]\n[HttpHeaders]\n
StringToSign = [q-sign-algorithm]\n[q-sign-time]\nSHA1-HASH(HttpString)\n
Signature = HMAC-SHA1(SignKey,StringToSign)

again Take a look at the complete algorithm of Signature:

$signTime = $qSignTime;
$signKey = hash_hmac('sha1', $signTime, $secretKey);
$httpString = "$httpMethod \n$httpUri\n$httpParameters\n$headerString\n";
$sha1edHttpString = sha1($httpString);
$stringToSign = "sha1\n$signTime\n$sha1edHttpString\n";
$signature = hash_hmac('sha1', $stringToSign, $signKey);

$signTime: very simple, a string consisting of start and end time, just use it from above
$ signKey: HMAC-SHA1 algorithm can be calculated directly
$httpString: The four parts need to be said separately
1, $httpMethod: HTTP request method, lowercase, such as put, get
2. $httpUri: The URI part of the HTTP request, starting from the "/" virtual root, such as /testfile means creating a file called testfile in the root directory of the bucket, /image/face1.jpg means creating a file called testfile in the root directory/image directory. Create a file called face1.jpg. As for whether it is an image file or not, it doesn’t matter
3, $httpParameters: This is the first place to be careful. It consists of HTTP original request parameters, that is, the part after ? in the request URI. This example calls the PUT Object interface, so it is empty. If it is not empty, you need to convert the key and value of each item of the request parameter to lowercase. Multiple pairs of key=value are sorted by dictionary and connected with &
4. $headerString: This is the second place to be careful. , consisting of HTTP original request headers. According to the request headers, select all or part of the request headers, convert the keys of each item to lowercase, convert the values ​​to URLEncode, change the format of each item to key=value, and then proceed according to the key. Dictionary sorting, and finally use the connector & to form a string. This is the logic I compiled. The code is as follows:

/**
 * 按COS要求从数组中获取 Signature 中 [HttpString] 内容
 * 标准格式 key=value&key=value&... 
 * 数组元素按键字典排序 * 
 * key转换为小写
 * value进行UrlEncode转换
 * 转换为key=value格式
 * 多对key=value之间用连接符连接
 * 
 */
function get_http_header_string($headers){
 if(!is_array($headers)){
  return false;
 }

 try{
  $tmpArray = array();
  foreach($headers as $key => $value){
   $tmpKey = strtolower($key);
   $tmpArray[$tmpKey] = urlencode($value);
  }
  ksort($tmpArray);
  $headerArray = array();
  foreach( $tmpArray as $key => $value){
   array_push($headerArray, "$key=$value");
  }
  return implode('&', $headerArray);
 }
 catch(Exception $error){
  return false;
 }
}

Why should you be careful?

HTTP original request headers and request parameters are used in four places, namely q-header-list in the request signature and HttpHeaders in the Signature - both use the HTTP original request header; request signature q-url-param-list in Signature and HttpParameters in Signature - both use HTTP request parameters. Be sure to ensure that the number of HTTP request headers and request parameters selected is consistent with the object

• : the number and members of the HTTP request headers generated by q-header-list must be the same as those used to generate HttpHeaders. The number and members of the HTTP request parameters generated by q-url-param-list must be the same as those generated by HttpParameters.

• is different: q-header-list and q-url-param-list only take In the key part, HttpHeaders and HttpParameters take the key and value parts

Output results and verification

At this point, there are 7 values ​​in the request signature Some of them come from user information, and some need to be calculated. All the calculation methods and personal understanding of why they are calculated are also given above. Finally, you only need to output according to the official requirements. take a look

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