Setting CORS Rules

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You can call set_bucket_cors_configuration() to set CORS rules for a bucket. If the bucket is configured with CORS rules, the newly set ones will overwrite the existing ones. Sample code is as follows:

Parameter Description

Field	Type	Mandatory or Optional	Description
option	The context of the bucket. For details, see Configuring option.	Mandatory	Bucket parameter
obs_cors_conf_info	obs_bucket_cors_conf *	Mandatory	For details about CORS rules, see the following table.
conf_num	unsigned int	Mandatory	Number of array members in the array obs_cors_conf_info.
handler	obs_response_handler*	Mandatory	Callback function
callback_data	void *	Optional	Callback data

The following table describes the CORS rule structure obs_bucket_cors_conf.

Field	Type	Mandatory or Optional	Description
id	const char *	Optional	Object names in a bucket
allowed_method	const char **	Mandatory	Method allowed by a CORS rule
allowed_method_number	unsigned int	Mandatory	Number of allowed_method
allowed_origin	const char **	Mandatory	Indicates an origin that is allowed by a CORS rule. It is a character string and can contain a wildcard (), and allows one wildcard character () at most.
allowed_origin_number	unsigned int	Mandatory	Number of allowed_origin.
allowed_header	const char **	Optional	Indicates which headers are allowed in a PUT Bucket CORS request via the Access-Control-Request-Headers. If a request contains Access-Control-Request- Headers, only a CORS request that matches the configuration of allowed_header is considered as a valid request. Each allowed_header can contain at most one wildcard (*) and cannot contain spaces.
allowed_header_number	unsigned int	Optional	Number of allowed_header
max_age_seconds	const char *	Optional	Response time of CORS that can be cached by a client. It is expressed in seconds. Each CORS rule can contain only one max_age_seconds. It can be set to a negative value.
expose_header	const char **	Optional	Indicates a supplemented header in CORS responses. The header provides additional information for clients. It cannot contain spaces.
expose_header_number	unsigned int	Optional	Number of expose_header.

Sample Code

static void test_set_bucket_cors()
{
    obs_options option;
    obs_status  ret_status = OBS_STATUS_BUTT;
    obs_bucket_cors_conf bucketCorsConf; 
    // Set option.
    init_obs_options(&option);
    option->bucket_options.hostName = "<your-endpoint>";
    option->bucket_options.bucketName = "<Your bucketname>";

    // Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables ACCESS_KEY_ID and SECRET_ACCESS_KEY.
    // Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/eu/usermanual-ca/ca_01_0003.html.
    option->bucket_options.access_key = getenv("ACCESS_KEY_ID");
    option->bucket_options.secret_access_key = getenv("SECRET_ACCESS_KEY");
    // Set callback function.
    obs_response_handler response_handler =
    { 
        NULL, &response_complete_callback
    };

    char *id_1= "1"; 
    // Specify the browser's cache time of the returned results of OPTIONS requests for specific resources, in seconds.
    char *max_age_seconds = "100";
    // Specify the request method, which can be GET, PUT, DELETE, POST, or HEAD.
    const char* allowedMethod_1[5] = {"GET","PUT","HEAD","POST","DELETE"};
    // Specify the origin of the cross-domain request.
    const char* allowedOrigin_1[2] = {"obs.example.com", "www.example.com"}; 
    // Specify response headers that users can access using application programs.
    const char* allowedHeader_1[2] = {"header-1", "header-2"}; 
    // Additional headers carried in the response
    const char* exposeHeader_1[2]  = {"hello", "world"}; 
    
    memset(&bucketCorsConf, 0, sizeof(obs_bucket_cors_conf)); 
    bucketCorsConf.id = id_1; 
    bucketCorsConf.max_age_seconds = max_age_seconds; 
    bucketCorsConf.allowed_method = allowedMethod_1; 
    bucketCorsConf.allowed_method_number = 5; 
    bucketCorsConf.allowed_origin = allowedOrigin_1;
    bucketCorsConf.allowed_origin_number = 2; 
    bucketCorsConf.allowed_header = allowedHeader_1; 
    bucketCorsConf.allowed_header_number = 2; 
    bucketCorsConf.expose_header = exposeHeader_1; 
    bucketCorsConf.expose_header_number = 2; 
    
    set_bucket_cors_configuration(&option, &bucketCorsConf, 1, &response_handler, &ret_status); 
    if (OBS_STATUS_OK == ret_status) {
        printf("set_bucket_cors success.\n");
    }
    else {
        printf("set_bucket_cors faied(%s).\n", obs_get_status_name(ret_status));
    }
}

allowed_origin, allowed_method, and allowed_header can contain at most one wildcard (*). Wildcard characters (*) indicate that all origins, operations, or headers are allowed.

Parent topic: Cross-Origin Resource Sharing (CORS)

Previous topic: CORS Overview

Next topic: Viewing CORS Rules