FetchRemote: Difference between revisions

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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.
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.
{{Note|Client side function only works with the server the player is connected to unless the domain has been accepted with [[requestBrowserDomains]]}}
{{ Warning| function won't trigger inside another fetchRemote function }}
{{ Warning| When using [[toJSON]] for submitting data, make sure to use '''string.sub(data, 2, -2)''' to remove the initial and final brackets, as many APIs will not understand the request }}
 
{{Legacy|legacy/fetchRemote}}


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.
{{Note|Client side function only works with the server the player is connected to or it will return the error #1006}}
==Syntax==  
==Syntax==  
<syntaxhighlight lang="lua">
<syntaxhighlight lang="lua">
bool fetchRemote ( string URL[, string queueName = "default" ][, int connectionAttempts = 10, int connectTimeout = 10000 ], function callbackFunction, [ string postData = "", bool postIsBinary = false, [ arguments... ] ] )
bool fetchRemote ( string URL[, table options ], callback callbackFunction[, table callbackArguments ] )
</syntaxhighlight>  
</syntaxhighlight>


===Required Arguments===  
===Required Arguments===  
*'''URL:''' A full URL in the format ''<nowiki>http://hostname/path/file.ext</nowiki>''. A port can be specified with a colon followed by a port number appended to the hostname.
*'''URL:''' A full URL in the format ''<nowiki>http://hostname/path/file.ext</nowiki>''. 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:
*'''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
**'''''responseData''''' - A string containing the remote response
**'''''errno''''' - A number containing the error number or zero if there was no error. A list of possible error values are:
**'''''responseInfo''''' - A table containing:
***'''''success''''' - A boolean indicating if the request was successful.
***'''''statusCode''''' - An integer status/error code. See the list of possible error values below.
***'''''headers''''' - A table containing the HTTP response headers
**'''''arguments...''''' - The arguments that were passed into fetchRemote
 
===Callback '''statusCode''' error values===
{{Error_codes_for_callRemote_and_fetchRemote}}
{{Error_codes_for_callRemote_and_fetchRemote}}
<div style="padding-left:19px;">
*'''''arguments...''''' - The arguments that were passed into fetchRemote
</div>


===Optional Arguments===  
===Optional Arguments===  
{{New items|4.0153|1.5.3-9.11270|
*'''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.
**'''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)''
*'''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. ''(Defaults to 10000)''
*'''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.
*'''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)''
*'''postIsBinary :''' A boolean specifying if the data is text, or binary.
**'''method:''' A string specifying the request method. ''(Defaults to GET or POST)''
*'''arguments:''' Any arguments you may want to pass to the callback.
**'''headers:''' A table containing HTTP request headers. ''e.g.{ Pragma&#61;"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.
**'''formFields:''' A table containing form items to submit. (for POST method only)  ''e.g.{ name&#61;"bob", email&#61;"[email protected]" }''
*'''callbackArguments:''' A table containing arguments you may want to pass to the callback.


===Returns===
===Returns===
Returns ''true'' if the arguments are correct, ''false'' otherwise.
Returns a '''''request''''' value which can be used with [[GetRemoteRequestInfo|getRemoteRequestInfo]] or [[AbortRemoteRequest|abortRemoteRequest]]


==Example==
==Example==
This example shows you how you can fetch an image from a web page, and transfer it to a particular client:
<section name="Server - Example 1" class="server" show="true">
<section name="Server" class="server" show="true">
Sending email via a web service (adopted from examples on https://documentation.mailgun.com/en/latest/user_manual.html)
<syntaxhighlight lang="lua">
<syntaxhighlight lang="lua">
sendOptions = {
    queueName = "My Mailgun queue",
    connectionAttempts = 3,
    connectTimeout = 5000,
    formFields = {
        from="Excited User <[email protected]>",
        to="[email protected]",
        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 startImageDownload( playerToReceive )
function mailgunCompleteCallback(data, info)
     fetchRemote ( "http://www.example.com/image.jpg", myCallback, "", false, playerToReceive )
     outputDebugString( "mailgunComplete"
end
            .. " success:" .. tostring(info.success)
 
            .. " statusCode:" .. tostring(info.statusCode)
function myCallback( responseData, errno, playerToReceive )
            .. " data:" .. tostring(data)
    if errno == 0 then
            )
        triggerClientEvent( playerToReceive, "onClientGotImage", resourceRoot, responseData )
    end
end
end
</syntaxhighlight>
</syntaxhighlight>
</section>
</section>


<section name="Client" class="client" show="true">
<section name="Server - Example 2" class="server" show="true">
Changing post content of an IPS forum thread via its API.
<syntaxhighlight lang="lua">
<syntaxhighlight lang="lua">
addEvent( "onClientGotImage", true )
local apiKey = "12345678123456781234567812345678" -- key from ips admin panel
addEventHandler( "onClientGotImage", resourceRoot,
local forumAddress = "https://yourForum.com"
     function( pixels )
function setPostContent(postID,content)
        if myTexture then
  local sendOptions = {
            destroyElement( myTexture )
    queueName = "updatePost",
        end
    connectionAttempts = 1,
        myTexture = dxCreateTexture( pixels )
     connectTimeout = 50,
    end
    formFields = {
)
      post = content,
    },
  }
  fetchRemote( forumAddress.."/api/forums/posts/"..postID.."?key="..apiKey, sendOptions, function()end)
end


addEventHandler("onClientRender", root,
setPostContent(1, "this is a first post on this forum")
    function()
        if myTexture then
            local w,h = dxGetMaterialSize( myTexture )
            dxDrawImage( 200, 100, w, h, myTexture )
        end
    end
)
</syntaxhighlight>
</syntaxhighlight>
</section>
</section>
==Requirements==
{{Requirements|1.3.0-9.03739|1.3.2|}}
==Changelog==
{{ChangelogHeader}}
{{ChangelogItem|1.3.1-9.04605|Added connectionAttempts argument}}
{{ChangelogItem|1.3.2|Added client side}}
{{ChangelogItem|1.5.3-9.11270|Added queueName argument}}


==See Also==
==See Also==
{{Resource_functions}}
{{Resource_functions}}

Latest revision as of 07:05, 13 November 2024

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.

[[{{{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
[[|link=|]] Warning: When using toJSON for submitting data, make sure to use string.sub(data, 2, -2) to remove the initial and final brackets, as many APIs will not understand the request


Dialog-info.png This page describes the current implementation. For older versions check legacy version


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. See the list of possible error values below.
      • headers - A table containing the HTTP response headers
    • arguments... - The arguments that were passed into fetchRemote

Callback statusCode error values

  • 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

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.
    • formFields: A table containing form items to submit. (for POST method only) e.g.{ name="bob", email="[email protected]" }
  • callbackArguments: A table containing arguments you may want to pass to the callback.

Returns

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

Example

Click to collapse [-]
Server - Example 1

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

sendOptions = {
    queueName = "My Mailgun queue",
    connectionAttempts = 3,
    connectTimeout = 5000,
    formFields = {
        from="Excited User <[email protected]>",
        to="[email protected]",
        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
Click to collapse [-]
Server - Example 2

Changing post content of an IPS forum thread via its API.

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")

See Also