HTTP_GET()

Syntax

Result as P = HTTP_GET( URL as C [, Cookie as C [, Port as N [, Timeout as N [, Show_Before_Send as L [, Validate_SSL_Certificate as L ]]]]] )

Argument	Description
Result	A dot variable containing the server's response.
	Argument	Type	Description
	.error_text	C	The error message, if any.
	.error_code	N	The error number, if any.
	.headers	C	Response headers.
	.body	B	Response body.
URL	The URL of the page to retrieve.
Cookie	Optional. Default = "". Cookie data. Limited to 8 MBytes.
Port	Optional. Default = -1. The port to use.
Timeout	Optional. Default = 8000 milliseconds. The number of milliseconds to wait before timing out.
Show_Before_Send	Optional. Default = .F.. When .T., displays the request before being sent. Useful for debugging.
Validate_SSL_Certificate	Optional. 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 set to .F., the request may succeed, but the server's identity is not guaranteed.

Description

The HTTP_GET() function downloads from a URL using HTTP/1.1 GET. The function supports cookies and returns a pointer with the parsed response from the server.

Note : When the server responds with a 302 code, HTTP_GET() 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.

The parsed response will include several elements, including the following.

Argument	Example
Result.parsed_headers.ContentType	"text/html"
Result.parsed_headers.ContentLength	"12541"
Result.parsed_headers.Date	"Wed, 30 Jun 2004 14:36:12 GMT"
Result.parsed_headers.Server	"Microsoft-IIS/5.0"

Note : A HTTP GET is different from a HTTP POST in two significant ways. Some devices may restrict the total length of a URL to 128 characters, which may trim the arguments appended by a GET command. There is no such restriction with POST commands. You may save (bookmark) and refresh URLs formatted through a HTTP GET command. The arguments sent by a HTTP POST command are not saved in a bookmark.

Supported By

Alpha Five Version 6 and Above

Examples

The following example follows a redirect.

dim url as C = "support.alphasoftware.com"

dim result as P

result = http_fetch(url)

if (result.parsed_headers.status_code = 302) then

result = http_get(result.parsed_headers.Location)

...

end if

Retrieve the Alpha Software home page.

dim alpha as P

alpha = http_get("http://www.alphasoftware.com/")

a5_show_html(alpha.body)

Search Google.

dim search_term as C

dim google as P

search_term = ui_get_text("Search for...","What are you looking for?")

google = http_get("http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=" + urlencode(search_term))

a5_show_html(google.body)

Retrieve RSS text from Slashdot.org.

dim rss as P

rss = http_get("http://slashdot.org/index.rss")

if .not. eval_valid("rss.body")

ui_msg_box("Error","The RSS file was not downloaded from the server.",UI_STOP_SYMBOL)

else

dim num_items as N

num_items = count_textblocks(rss.body,"<item","</item>")

dim item[num_items] as P

dim i as N

dim this_item as C

for i = 1 to num_items

this_item = extract_string(rss.body,"<item","</item>",i,.t.)

item[i].title = extract_string(this_item,"<title>","</title>")

item[i].link = extract_string(this_item,"<link>","</link>")

item[i].description = extract_string(this_item, "<description>", "</description>")

item[i].creator = extract_string(this_item, "<dc:creator>", "</dc:creator>")

item[i].subject = extract_string(this_item, "<dc:subject>", "</dc:subject>")

item[i].date = extract_string(this_item, "<dc:date>", "</dc:date>")

item[i].section = extract_string(this_item, "<slash:section>", "</slash:section>")

item[i].department = extract_string(this_item, "<slash:department>", "</slash:department>")

item[i].comments = extract_string(this_item, "<slash:comments>", "</slash:comments>")

item[i].hitparade = extract_string(this_item, "<slash:hitparade>", "</slash:hitparade>")

next i

'now do something with this, like put it into a table or build an output file.

a5_show_variable(property_to_string(item))

end if