Common Parameters

Amazon S3 REST requests include headers that contain basic information about the request. The following table describes headers that are common to all Amazon S3 REST requests.

Header Name	Description	Required
`Content-Length`	Length of the message (without the headers) according to RFC 2616. Type: String Default: None Condition: Required for PUTs and operations that load XML, such as logging and ACLs.	Conditional
`Content-Type`	The content type of the resource. Example: `text/plain` Type: String Default: None	No
`Date`	The current date and time according to the requester. Example: `Wed, 01 Mar 2006 12:00:00 GMT` Type: String Default: None	Yes
`Host`	Normally, the value of Host is `s3.amazonaws.com`. A Host header with a value other than `s3.amazonaws.com` selects the bucket for the request as described in Virtual Hosting of Buckets. Type: String Default: None Condition: Required for HTTP 1.1 (most toolkits add this header automatically); optional for HTTP/1.0 requests.	Conditional
`Authorization`	The information required for request authentication. For more information, see The Authentication Header for details about the format. Type: String Default: None	Yes
`x-amz-security-token`	The security tokens for operations that use Amazon DevPay. Each request that uses Amazon DevPay requires two `x-amz-security-token` headers: one for the product token and one for the user token. When Amazon S3 receives an authenticated request, it compares the computed signature with the provided signature. Improperly formatted multi-value headers used to calculate a signature can cause authentication issues. To ensure the signature is calculated properly, follow the instructions in the Constructing the CanonicalizedResource Element section. Type: String Default: None Condition: Required for requests that use Amazon DevPay.	Conditional