Scripting application
HTTP scripts are composed of several functional components that define the trigger events, commands, operators, and more. The following example demonstrates how HTTP scripting is applied to rewrite the HTTP Host header and path in an HTTP request.
The HTTP script:
when RULE_INIT {
debug("rewrite the HTTP Host header and path in a HTTP request \n")
}
when HTTP_REQUEST{
host = HTTP:header_get_value("Host")
path = HTTP:path_get()
if host:lower():find("myold.hostname.com") then
debug("found myold.hostname.com in Host %s \n", host)
HTTP:header_replace("Host", "mynew.hostname.com")
HTTP:path_set("/other.html")
end
}
Script component breakdown:
|
Parameter |
Example |
Description |
|---|---|---|
|
Events — for details, see Events and actions. |
||
|
RULE_INIT |
The event is used to initialize global or static variables used within a script. It is triggered when a script is added or modified, or when the device starts up, or when the software is restarted. | |
|
|
HTTP_REQUEST |
The virtual server receives a complete HTTP request header. |
|
Commands — for details, see Predefined commands. |
||
|
Debug(str) |
Prints the debug information when VS using scripting. | |
|
|
HTTP:header_get_values(header_name) |
Returns a list of value(s) of the HTTP header named <header_name>, with a count for each value. Note that the command returns all the values in the headers as a list if there are multiple headers with the same name. |
|
|
HTTP:path_get() |
Returns the string of the HTTP request path. |
|
|
HTTP:header_replace(header_name, value) |
Replaces the occurrence value of header <header_name> with value <value>. |
|
|
HTTP:path_set(value) |
Sets HTTP request path to the string <value>. |
|
Operators — for details, see Operators. (Not applicable in this example). |
||
| Strings — for details, see String library. | ||
|
|
host:lower():find("myold.hostname.com") |
The string library includes the string-manipulation functions, such as:
This example combines the above string manipulation functions, using |
| Control structures — for details, see Control structures. | ||
|
if...then end |
if condition1 then … else if condition2 then … break else … go to location1 end
::location1:: |
|
|
Functions — for details, see Functions. (Not applicable in this example). |
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