FetchRemote

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Revision as of 18:34, 25 July 2020 by Haxardous (talk | contribs)

This function allows you to post and receive data from HTTP servers. The calls are asynchronous so you do not get an immediate result from the call, instead a callback function you specify is called when the download completes.

In the case when the call fails, a string containing "ERROR" followed by an integer containing the error reason will be passed to the callback function. The reason for failure will be similar to errors found with websites - file not found, server not found and timeouts.

If you are using fetchRemote to connect to a PHP script, you can use file_get_contents("php://input") to read the postData sent from this function.

[[{{{image}}}|link=]] Note: Client side function only works with the server the player is connected to unless the domain has been accepted with requestBrowserDomains
[[|link=]] Warning: function won't trigger inside another fetchRemote function

Syntax

bool fetchRemote ( string URL, [ string queueName = "default" ], [ int connectionAttempts = 10, int connectTimeout = 10000 ], function callbackFunction, [ string postData = "",  bool postIsBinary = false ], [ arguments... ] )

Required Arguments

  • URL: A full URL in the format http://hostname/path/file.ext. A port can be specified with a colon followed by a port number appended to the hostname.
  • callbackFunction: This is the function that should receive the data returned from the remote server. The callback argument list should be:
    • responseData - A string containing the remote response or "ERROR" if there was a problem
    • error - A number containing the error number or zero if there was no error. A list of possible error values are:
  • 1-89: See cURL website or its mirror at cURL errors
  • 400-599: See HTTP status codes
  • 1002: Download aborted
  • 1003: Failed to initialize
  • 1004: Unable to parse url
  • 1005: Unable to resolve host name
  • 1006: Destination IP not allowed
  • 1007: File error
  • arguments... - The arguments that were passed into fetchRemote

Optional Arguments

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  • queueName: Name of the queue to use. Any name can be used. If not set, the queue name is "default". Requests in the same queue are processed in order, one at a time.
  • connectionAttempts: Number of times to retry if the remote host does not respond. In the case of a non-responding remote server, each connection attempt will timeout after 10 seconds. Therefore, the default setting of 10 connection attempts means it will be 100 seconds before your script gets a callback about the error. Reducing this value to 2 for example, will decrease that period to 20 seconds
  • connectTimeout: Number of milliseconds each connection attempt will take before timing out
  • postData: A string specifying any data you want to send to the remote HTTP server.
  • postIsBinary : A boolean specifying if the data is text, or binary.
  • arguments: Any arguments you may want to pass to the callback.


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Syntax

bool fetchRemote ( string URL[, table options ], callback callbackFunction[, table callbackArguments ] )

Required Arguments

  • URL: A full URL in the format http://hostname/path/file.ext. A port can be specified with a colon followed by a port number appended to the hostname.
  • callbackFunction: This is the function that should receive the data returned from the remote server. The callback argument list should be:
    • responseData - A string containing the remote response
    • responseInfo - A table containing:
      • success - A boolean indicating if the request was successful.
      • statusCode - An integer status/error code
      • headers - A table containing the HTTP response headers
    • arguments... - The arguments that were passed into fetchRemote

Optional Arguments

  • options: A table containing any request options:
    • queueName: Name of the queue to use. Any name can be used. If not set, the queue name is "default". Requests in the same queue are processed in order, one at a time.
    • connectionAttempts: Number of times to retry if the remote host does not respond. (Defaults to 10)
    • connectTimeout: Number of milliseconds each connection attempt will take before timing out. (Defaults to 10000)
    • postData: A string specifying any data you want to send to the remote HTTP server.
    • postIsBinary : A boolean specifying if the data is text, or binary. (Defaults to false)
    • method: A string specifying the request method. (Defaults to GET or POST)
    • headers: A table containing HTTP request headers. e.g.{ Pragma="no-cache" }
    • maxRedirects: An integer limiting the number of HTTP redirections to automatically follow. (Defaults to 8)
    • username: A string specifying the username for protected pages.
    • password: A string specifying the password for protected pages.
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    • formFields: A table containing form items to submit. (for POST method only) e.g.{ name="bob", email="bob@example.com" }
  • arguments: A table containing arguments you may want to pass to the callback.

Returns

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Returns a request value which can be used with getRemoteRequestInfo or abortRemoteRequest

Example

This example shows you how you can fetch an image from a web page, and transfer it to a particular client:

Click to collapse [-]
Server

function startImageDownload( playerToReceive )
    fetchRemote ( "http://www.example.com/image.jpg", myCallback, "", false, playerToReceive )
end

function myCallback( responseData, error, playerToReceive )
    if error == 0 then
        triggerClientEvent( playerToReceive, "onClientGotImage", resourceRoot, responseData )
    end
end
Click to collapse [-]
Client
addEvent( "onClientGotImage", true )
addEventHandler( "onClientGotImage", resourceRoot,
    function( pixels )
        if myTexture then
            destroyElement( myTexture )
        end
        myTexture = dxCreateTexture( pixels )
    end
)

addEventHandler("onClientRender", root,
    function()
        if myTexture then
            local w,h = dxGetMaterialSize( myTexture )
            dxDrawImage( 200, 100, w, h, myTexture )
        end
    end
)


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Example sending email via a web service (adopted from examples on https://documentation.mailgun.com/user_manual.html)

Click to collapse [-]
Server
sendOptions = {
    queueName = "My Mailgun queue",
    connectionAttempts = 3,
    connectTimeout = 5000,
    formFields = {
        from="Excited User <excited@samples.mailgun.org>",
        to="devs@mailgun.net",
        subject="Hello",
        text="Testing some Mailgun awesomness!",
    },
    username="api",
    password="key-3ax6xnjp29jd6fds4gc373sgvjxteol0",
}
fetchRemote( "https://api.mailgun.net/v3/samples.mailgun.org/messages", sendOptions, mailgunCompleteCallback )

function mailgunCompleteCallback(data, info)
    outputDebugString( "mailgunComplete"
            .. " success:" .. tostring(info.success)
            .. " statusCode:" .. tostring(info.statusCode)
            .. " data:" .. tostring(data)
            )
end

Changing post content on IPS forum.

Click to collapse [-]
Server
local apiKey = "12345678123456781234567812345678" -- key from ips admin panel
local forumAddress = "https://yourForum.com"
function setPostContent(postID,content)
  local sendOptions = {
    queueName = "updatePost",
    connectionAttempts = 1,
    connectTimeout = 50,
    formFields = {
      post = content,
    },
  }
  fetchRemote( forumAddress.."/api/forums/posts/"..postID.."?key="..apiKey, sendOptions, function()end)
end

setPostContent(1, "this is a first post on this forum")

Requirements

Minimum supported server 1.3.0-9.03739
Minimum supported client 1.3.2

Note: Using this function requires the resource to have the above minimum version declared in the meta.xml <min_mta_version> section. e.g. <min_mta_version server="1.3.0-9.03739" client="1.3.2" />

Changelog

Version Description
1.3.1-9.04605 Added connectionAttempts argument
1.3.2 Added client side
1.5.3-9.11270 Added queueName argument
1.5.4-9.11342 Added alternative syntax
1.5.4-9.11413 Added formFields

See Also

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