1# Network and Connection Development 2 3 4 5## What are the data formats supported by extraData in an HTTP request? 6 7Applicable to: OpenHarmony SDK 3.2.2.5, stage model of API version 9 8 9**extraData** indicates additional data in an HTTP request. It varies depending on the HTTP request method. 10 11- If the HTTP request uses a POST or PUT method, **extraData** serves as the content of the HTTP request. 12 13- If the HTTP request uses a GET, OPTIONS, DELETE, TRACE, or CONNECT method, **extraData** serves as a supplement to the HTTP request parameters and will be added to the URL when the request is sent. 14 15- If you pass in a string object, **extraData** contains the string encoded on your own. 16 17 18## What does error code 28 mean for an HTTP request? 19 20Applicable to: OpenHarmony SDK 3.2.2.5, stage model of API version 9 21 22Error code 28 refers to **CURLE_OPERATION_TIMEDOUT**, which means a cURL operation timeout. For details, see any HTTP status code description available. 23 24Reference: [Response Codes](../reference/apis/js-apis-http.md#responsecode) and [Curl Error Codes](https://curl.se/libcurl/c/libcurl-errors.html) 25 26 27## What does error code 6 mean for the response of \@ohos.net.http.d.ts? 28 29Applicable to: OpenHarmony SDK 3.2.3.5 30 31Error code 6 indicates a failure to resolve the host in the address. You can ping the URL carried in the request to check whether the host is accessible. 32 33Reference: [Response Codes](../reference/apis/js-apis-http.md#responsecode) and [Curl Error Codes](https://curl.se/libcurl/c/libcurl-errors.html) 34