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API fundamentals

This section presents general information (such as message structure, message fields, and message transmission) of online messages between your system and Alipay. A message refers to the request message or the response message.

Request message structure 

The following figures illustrate the request message structure: 

image.png

Request URL 

The request URL is: https://{host}/openapi/v{majorVersion}/{restfulPath}

where, 

host is the standard domain name assigned by Alipay.

restfulPath is the path to the interface. 

An interface can be uniquely identified by restfulPath and majorVersion. 

Request method 

POST method is used to make an HTTP request. 

Request header 

The request header mainly contains fields such as Client-Id, Signature, Encrypt, Content-Type, Request-Time, and Agent-Token. 

Client-Id Required

Client-Id is used to identify a client, and is associated with the keys that are used for signature and encryption. It is assigned by AlipayHK.

Signature Required

Signature contains key-value pairs that are separated by comma (,). Each key-value pair is an equation, which is a key joined with its value with an equal sign (=). 

The following keys can be configured: 

  • algorithm: Specifies the digital signature algorithm that is used to generate the signature. The value is not case-sensitive. RSA256 and ECC224 are supported, and RSA256 by default. 
  • keyVersion: Specifies the key version that is used to generate or validate the signature. By default, the value is the latest version of the key associated with Client-Id. 
  • signature: Contains the signature value of the request. 

For example: 

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signature: algorithm=RSA256, keyVersion=1,
signature=KEhXthj4bJ801Hqw8kaLvEKc0Rii8KsNUazw7kZgjxyGSPuOZ48058UVJUkkR21iD9JkHBGR
rWiHPae8ZRPuBagh2H3qu7fxY5GxVDWayJUhUYkr9m%2FOW4UQVmXaQ9yn%2Fw2dCtzwAW0htPHYrKMyrT
pMk%2BfDDmRflA%2FAMJhQ71yeyhufIA2PCJV8%2FCMOa46303A0WHhH0YPJ9%2FI0UeLVMWlJ1XcBo3Jr
bRFvcowQwt0lP1XkoPmSLGpBevDE8%2FQ9WnxjPNDfrHnKgV2fp0hpMKVXNM%2BrLHNyMv3MkHg9iTMOD%
2FFYDAwSd%2B6%2FEOFo9UbdlKcmodJwjKlQoxZZIzmF8w%3D%3D

Encrypt Conditional

This field is required when a message need to be encrypted. Encrypt contains key-value pairs that are separated by comma (,). Each key-value pair is an equation, which is a key joined with its value with an equal sign (=). 

The following keys can be configured: 

• algorithm: Specifies the symmetric key algorithm that is used to encrypt message. The value is not case-sensitive, and currently only RSA_AES is supported. 

• keyVersion: Specifies the symmetric key version that is used to encrypt message. By default, the value is the latest version of the key associated with clientId. 

• symmetricKey: Contains the encrypted symmetric key. 

For example: 

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Encrypt: algorithm=RSA, keyVersion=1,
symmetricKey=bqS8HSmdaRrpKSuPy7CqUlyd8lJurG93

Content-Type Required

Optional. Content-Type indicates the media type of the body of the request, as defined by RFC2616. In which, charset is used for generating/validating the signature and encrypting/decrypting content. 

For example： 

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Content-Type: application/json; charset=UTF-8

Request-Time Required

Specifies the time when the request is sent, as defined by RFC3339. Note: This field must be accurate to milliseconds.

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Request-Time: 2019-04-04T12:08:56.253+05:30

Agent-Token Optional

An agent can obtain the token from Alipay, and then use this client authorized token to interact with Alipay. 

Request body 

The request body contains the detailed request information in a JSON format. Fields enclosed in the request body section vary depending on services. For more information, see instructions of the specific message interface. 

Response message structure

The following figures illustrate the response structure:

image

Figure 2. Response structure 

Response header 

Response header carries additional information about the response, such as the signature and the encryption. Most fields in the response header are the same as that of the request header, except:

Response-Time Required

Specifies the time when the response is sent, as defined by RFC3339.

Response body 

Response body contains the information responding to the client. Fields in this section vary depending on services. However, the result parameter, which indicates the result of an interface call, is always contained. 

Message fields 

Read the following chapter for general information of message fields, such as data type, common data structure, and processing rules of special characters. 

Data type

This following table describes the data types supported by Alipay. 

Data type 

Description 

String 

A sequence of bytes. 

Email 

Email format

URL 

URL format

Datetime 

Date time as defined by RFC3339. For example, 2020-01-01T23:59:59+08:00 

Date 

A three-part value (yyyyMMdd) designating a time point in time. 

Boolean 

The boolean value can be either true or false. 

Integer 

A numeric value without a decimal. 

Decimal 

A numeric value with a decimal. 

Array 

A homogeneous data structure (elements have same data type) that stores a sequence of consecutively numbered objects--allocated in contiguous memory. 

Processing rules of special characters 

The following rules are about how to process special characters enclosed in the message. 

base64 

For byte data, such as the signature and the encrypted content, encode the data with the base64 algorithm before transmitting. 

urlencode 

For URL data, perform URL encoding first before transmitting. For example: 

Original URL: https://www.merchant.com/authorizationResult 

Converted URL: https%3A%2F%2Fwww.merchant.com%2FauthorizationResult