Image Serving HTTP protocol basic syntax

The HTTP protocol basic syntax is as follows.

request

http:// server/is/image[/ object][? modifiers]

server

server_address[: port]

object

Source object specifier (image path or image catalog entry).

modifiers

modifier*[& modifier]

modifier

command|{$ macro$}|{. comment}

command

{ cmdName|{$ var}}[= value]

macro

Name of a command macro.

comment

Comment string (ignored by server).

cmdName

One of the supported command or attribute names.

var

Name of a custom variable.

value

Command or variable value.

server_address, cmdName, macro, and var are case-insensitive. The server preserves the case of all other string values.

value is command-specific and may consist of one or more values separated by commas. Refer to the description of the individual commands for details.

Server identifier

The /is/image root context is required for all HTTP requests to Image Serving.

HTTP decoding

Image Serving first extracts object and modifiers from the incoming request. object is then separated into path elements which are individually HTTP-decoded. The modifiers string is separated into command= value pairs, and value is then HTTP-decoded before command-specific processing.

NOTE

Unless otherwise noted in the documentation, all unsafe characters must be encoded per the HTTP standard. Refer to the HTTP specification for details.

Comments

Comments may be embedded into request strings anywhere and are identified by a period(.) immediately following the command separator(&). The comment is terminated by the next occurrence of an (unencoded) command separator. This feature may be used to add information to the request which is not for Image Serving use, such as time stamps, database ids, etc.

See also

Data Types, HTTP/1.1 Specification

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