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Calling APIs

Updated at: May 29, 2020 GMT+08:00

BCS provides RESTful APIs. REST-based web services are organized into resources. Each resource is identified by one or more Uniform Resource Identifiers (URIs). An application accesses a resource based on the resource's Uniform Resource Locator (URL).

A URL is usually in the format of "https://Endpoint/uri". uri indicates the resource path, that is, the API access path.

APIs use HTTP as the transmission protocol. Requests/Responses are transmitted by using JSON packets, with the media type represented by Application/json.

A RESTful API request or response consists of the following parts:

  • Request URI
  • Request header
  • Request body
  • Response header
  • Response body

Request URI

A request URI is in the following format:

{URI-scheme} :// {Endpoint} / {resource-path} ? {query-string}

Although a request URI is included in a request header, most programming languages or frameworks require the request URI to be separately transmitted, rather than being conveyed in a request message.

Table 1 Parameters in a URI




Protocol used to transmit requests. BCS APIs use HTTPS.


IP address and port number of the server bearing the RESTful service endpoint. To obtain the IP address, choose More > View Service Details in the Operation column of the purchased service listed on the Service Management page. The port number is fixed at 32621.


API access path for performing a specified operation. Only the chaincode invoking API is available now. Its path is fixed at /v1/chaincode/operation.


Not used.

Request Header

A request header consists of an HTTP method and custom fields.

  • HTTP-based request methods, which are also called operations or actions, specify the type of operations that you are requesting. The chaincode invoking RESTful API supports the following method.
Table 2 HTTP




Requests the server to update specified resources.

  • The following table lists the request header parameters customized for the chaincode invoking RESTful API.
Table 3 Customized header parameters





Signature of the chaincode invoking request message body



Encryption type, which is fixed at SW now.



Indication of whether GZIP compression is enabled. 0 indicates disabling, and 1 indicates enabling.


X-bcs-signature-sign: To ensure that only authorized invocation entities can invoke chaincodes, the user private key (downloaded by following Downloading the User Certificate) and the ECDSA encryption method must be used to encrypt and sign the SHA256 hash of the entire request body. The value of x-bcs-signature-sign is the encrypted and signed hash.

Request Body


Response Header

HTTP status code. A status code consists of three digits (2xx to 5xx). 2xx indicates a success response. 4xx and 5xx indicate failure responses. The status code returned can also be defined by the service.

Response Body

A response body conveys information other than the response header and is usually sent in a structured format (for example, JSON or XML) defined by the response header parameter Content-type.

Initiating a Request

A request can be initiated by using either of the following methods:

  • cURL

    cURL is a command line tool used to perform URL operations and transmit information. cURL acts as an HTTP client that can send HTTP requests to a server and receive response messages. cURL is suitable for use in API tuning scenarios. For more information about cURL, visit

  • Code

    You can call an API using code to assemble, send, and process requests.

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