Directory Opus Manual

HTTPRequest

The HTTPRequest object lets you easily send an asynchronous HTTP request to a remote webserver and receive and process the response.

This object is created via the Dialog object's NewHTTPReq method, and so requires a Script Dialog in order to use. The dialog also must be detached.

The general process to use this object is as follows:

Create the HTTPRequest object
Add any required headers
Add POST data or GET query name/value pairs as required
Send the request
Process "http" events in your message loop
Read any returned data when you get a "data" event.

Property Name	Return Type	Description
contenttype	string	When a response has been received, returns the value of the Content-Type response header.
complete	bool	Returns True when a request is complete (and all data has been received).
errorcode	int	Returns the numerical error code, if any.
errortext	string	Returns the error message, if any.
id	int	Returns the ID of the request. This is assigned automatically when the request is created. You'll need this if you use more than one request at once.
response	string	Returns the HTTP response message.
responsecode	int	Returns the HTTP response code (e.g. 200, 404).
status	string	Returns the current status of the request. This is also provided via the Msg.value property when you retrieve an HTTP message in your message loop. Valid status values are: notready, ready, pending, data, complete, error, shutdown. A status value of "data" means the response has been received and data is available to read. A status of "complete" means the response is complete (e.g. a HEAD request won't return any data, so you'd look for "complete" in that case).

Method Name	Arguments	Return Type	Description
Abort	none	none	Aborts the request if it hasn't yet returned any data, and removes any headers and post data that you've added. Calling this method resets the HTTPRequest object to its initial state, meaning it can be reused to send another request.
AddHeader	<string:name> <string:value> or <Map:headers>	none	Adds one or more headers to the HTTP request. You can either provide two strings (a name and a value), or a Map of name → value pairs to add more than one header at once.
AddPostData	<string:name> <value> [<string:contenttype>] [<string:filename>] [<string::encoding>] or <Map:data>	none	Adds one or more name/value pairs to the request's POST data. You can either provide the name and value as two arguments, in which case you can also optionally provide a content type string. Alternatively, you can provide a Map of name → value pairs. The value of a posted data element can either be a string, or a Blob object to provide binary data. If you only add a single item of POST data you can leave the name empty (pass an empty string). This lets you, for example, POST data formatted as JSON - set the name to an empty string, the value to the JSON data in string form, and contenttype to application/json. If adding a Blob you can provide the filename argument which gives the receiving system a suggested filename to store the file under. You can also specify the encoding type - set to "base64" to have the Blob sent as base64-encoded data (otherwise by default it will be sent as binary). If you've encoded the data yourself you can specify another encoding type which will be passed as the value of the Content-Transfer-Encoding header. The data will be sent as multipart/form-data if you either pass a Blob object, or the Map contains more than one name/value pair.
AddQueryData	<string:name> <string:value> or <Map:data>	none	Adds one or more name/value pairs to the request's QUERY data. You can either provide the name and value as two arguments, or you can provide a Map of name → value pairs. The query data will be automatically url-encoded and appended to the request string when the request is sent.
GetResponseHeaders	none	Map	Returns a Map of name → value pairs containing the response headers once the response data has been received.
ReadResponse	none	string or Image or Blob	Once a response has been received (i.e. your message loop gets an "http" message with the value type set to "data"), you can call this function to read the returned data. Note that this function will block until all data is received. The function tries to interpret the returned data automatically based on the Content-Type header in the response. Text data wil be converted to a string if possible. Image data will be returned as Image object if it's a format that Opus recognises. Otherwise, a Blob containing the response data will be returned.
ReadResponseData	[<int:size>]	Blob	Use this function instead of ReadResponse to read the raw data from the response without trying to interpret it. The data is returned as a Blob object. You can specify the maximum about of data to read in bytes. If the requested size is available it will be returned; otherwise the function will return immediately with as much data as possible. If you specify size as 0, or don't specify a size, then the function will block until the entire response has been received. If you specify size as -1 then the function will return as much data as possible, but won't block.
SendRequest	<string:url> [<string:action>]	none	Sends the HTTP request to the specified webserver. The url parameter should be the full URL to retrieve (e.g. https://www.gpsoft.com.au). If you've added any query parameters via the AddQueryData method these will be appended automatically. By default HTTP action will be chosen automatically based on the state of the object - POST if AddPostData has been used, otherwise GET. You can override this with the optional action parameter if you like - e.g. specify HEAD to just retrieve the headers without any response data.
SetTimeout	<int:seconds>	none	Specifies a timeout in seconds (default is 30). Functions which block like ReadResponse will timeout if a complete response is not received in time. Set to 0 for no timeout.
SetUserAgent	<string:agent>	none	Specifies the User-Agent string of the request, if requires.
Shutdown	none	none	Call this to close down the request and free any associated resources. This aborts the request if it's still outstanding. Once you've called this function you can't query the request for any other data except the complete property. You don't need to call this function but if you use a lot of requests you may want to once they're completed in order to free up memory. Once Shutdown has been called the request object can no longer be used. Note that messages from the request may still be in your dialog's message queue even after calling Shutdown - best practice is to check the complete property before using any other methods or properties.

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HTTPRequest