On Jul 21, 2007, at 11:58, Joakim Krassman wrote:
> Is there
> anyone that do have a code snippet that actually tells me the exactly
> weight
> of all the content that the httpclient downloaded?
There is no way for any client to know the entire weight of all content
without requesting each piece individually. Like Arno said in his
response, you can call HEAD for each item and check the Content-Length
header returned (if supported) without having to actually download
everything. You _do_ need to download the main document first in order
to parse it.
This is how the HTTP protocol works; the fact that Web browsers make it
look seemlessly as a single request and operation is mostly
behind-the-scenes "magic". If you pay close attention, particularly on
a slow connection, you'll see the "Progress Bar" in your browser
stretch and contract constantly as it updates the "total size" when it
finds images and other media while parsing the document (that's why
usually the text is rendered before the images start loading).
The HttpCli component in ICS does not provide this feature
automatically, but it shouldn't be too hard to implement. For parsing
the document and extracting all urls for image, css, js, and other
external resources, you can use any one of the many open source HTML
parsers out there (I even believe the JEDI project has a couple).
Implementing your own parser shouldn't be that hard either: recall that
you are not interested in understanding all layout information; you are
only looking for things that look like <img src=...> and the like.
So, to recap, here's a simple algorithm for doing what you requested:
1. GET document;
2. TOTAL_BYTES = Content-Length;
3. ResourceList := extract_resources(document);
4. For i := 0 To (ResourceList.Count - 1)
4.a. HEAD resource[i];
4.b. TOTAL_BYTES = TOTAL_BYTES + Content-Length;
5. Next;
dZ.
--
DZ-Jay [TeamICS]
http://www.overbyte.be/eng/overbyte/teamics.html
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