A dot variable containing instructions for the command. Pointer
The host (server) from which to download.Do not include the protocol (HTTP:// or HTTPS://) in the value
Default = 80 for HTTP (.ssl_on=.f.) and 443 for HTTPS (.ssl_on=.t.). The TCP/IP port on the server with which to communicate.
Default = "/". The page to request from the server.
The query string for the request.
Default = "GET". The HTTP method to use when making the request (GET, POST, HEAD, OPTIONS, etc).
Default = "HTTP/1.1". The protocol to use for the request.
Default = "". Sets the User-agent header in the request.
Default = "". Sets the value of the Cookie header.
Default = "". The contents of the HTTP request body.
Default = "". Sets the Referer header in the request.
Default = 45000 (45 seconds). Sets the timeout value, in milliseconds, for the connection.
Default = "". Allows setting of arbitrary headers. Would be used as: settings.header = "X-Header: I like Alpha Software"
Default = .F.
Default = .T.. If the specified URL starts with "https://", this flag controls whether or not the certificate offered by the server will be validated. If set to .T., the request will always fail if the certificate cannot be validated. If set to .F., the request may succeed, but the server's identity is not guaranteed.
Default = .F.. When .T., displays the request before being sent. Useful for debugging. Show_Before_Send is ignored if http_fetch is run from an A5W page.
SSL Cipher List
A dot variable containing the server's response.
The error message, if any. If no error occurs, error_text will be empty.
The error number, if any. If no error occurs, error_code will be 0.
Response headers. If error_code is 0, the result will contain a dot variable, parsed_headers, with a property representing each response header.
Contains all the headers in the response split out into individual properties. If an error occurred when trying to communicate with the server, parsed_headers will be empty. parsed_headers will always contain the following properties in addition to the headers in the response:
The HTTP version used.
A description of the status code.
The response status code. See Status Codes for a list of status codes.
Sends an HTTP request to a server and retrieves the response
The HTTP_FETCH() function sends an HTTP request to a server and receives the response. The function looks to see if a request body has been defined first. If one is found, and no .method has been specified, it uses POST, otherwise it uses GET. If a .method has been specified, that method will always be used, even if it is not a valid HTTP method. Similarly, if a .body is specified and the .method is not POST or PUT, the body is not sent.
If error_code is "0", parsed_response will contain the headers in the result. The parsed headers will contain every header sent in the response, as well as the status_code, reason_phrase, and http_version. The status_code should always be checked when the response is received. The example below shows what headers may be available in the result:
dim settings as P dim settings.host as C = "www.alphasoftware.com" dim settings.page as C = "/" dim result as P result = http_fetch(settings) ? result.error_code = 0 ? result.parsed_headers = AcceptRanges = "none" CacheControl = "private" Connection = "close" ContentLength = "47222" ContentType = "text/html" Date = "Thu, 22 Dec 2016 22:11:23 GMT" http_version = "HTTP/1.1" reason_phrase = "OK" Server = "Microsoft-IIS/8.5" SetCookie = "ASPSESSIONIDQSTBASCQ=KGOAFDNBPPOBEOIJOFEDADFA; path=/" status_code = 200 XPoweredBy = "ASP.NET"
Status code 200 indicates that the page exists. Status code 404 indicates that it does not. Other status codes you may encounter, along with the meanings of each, are documented in Status Codes.
When the server responds with a 30* code, HTTP_POST() does not automatically use the new URL. The developer needs to examine result.parsed_headers.status_code, then if appropriate, try the URL provided in result.parsed_headers.location. Refer to HTTP_GET() for an example.
The following example tests for the availability of a page:
dim settings as P dim result as P settings.host = "downloads.alphasoftware.com" settings.page = "/books/userguide.pdf" settings.method = "HEAD" result = http_fetch(settings) if (result.error_code <> 0) then ui_msg_box("Error communicating with server. Error code " + result.error_code + ": " + result.error_text) else if (result.parsed_headers.status_code = 200) then a5_show_html(result.body) else ui_msg_box(result.parsed_headers.status_code + ": " + result.parsed_headers.reason_phrase) end if end if
Validation is applied to the host specified for the HTTP request. If a full URL has been specified as the host name, the validation logic will extract the host name from the URL, allowing the HTTP request to be completed.