Cerebrus' right, and some research on request types would do wonders.

Some fiddling with the FMCSA website turned in some interesting
findings, tho.

There's two parameters being passed via POST, pv_apcant_id and
pv_vpath. The HTTP request header follows:

---x---
POST http://li-public.fmcsa.dot.gov/LIVIEW/pkg_carrquery.prc_getdetail
HTTP/1.0

Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg,
application/x-shockwave-flash, application/x-ms-application,
application/x-ms-xbap, application/vnd.ms-xpsdocument, application/xaml
+xml, application/vnd.ms-excel, application/vnd.ms-powerpoint,
application/msword, */*
Referer:
http://li-public.fmcsa.dot.gov/LIVIEW/pkg_carrquery.prc_carrlist?n_dotno=204961&s_prefix=MC&n_docketno=&s_legalname=&s_dbaname=&s_state=
Accept-Language: us-en
Content-Type: application/x-www-form-urlencoded
UA-CPU: x86
Proxy-Connection: Keep-Alive
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET
CLR 2.0.50727; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022; .NET CLR
3.0.4506.2152; .NET CLR 3.5.30729)
Pragma: no-cache
Content-Length: 34
Host: li-public.fmcsa.dot.gov

pv_apcant_id=16499&pv_vpath=LIVIEW
---x---

When i tried to apply them directly on the URL, it worked like a
charm.

http://li-public.fmcsa.dot.gov/LIVIEW/pkg_carrquery.prc_getdetail?pv_apcant_id=16499&pv_vpath=LIVIEW

It happens because some request implementations (ASP comes to my mind)
checks both collections, QueryStrings and Forms, in order to produce a
result. Seems this site works like this.

Hope it helps!

Cheers,
- Leon


On Feb 16, 8:31 am, Cerebrus <[email protected]> wrote:
> There are a number of things that you need to understand about HTTP
> and request types (GET/POST), most of which cannot be explained in a
> discussion thread like this... you will need to research them.
>
> POST requests do not append all form information in the URL as GET
> requests do. I want to clarify that it does not make a difference if
> the form parameters are hidden fields, since this appears to be the
> main aspect that's bothering you. This form uses a POST request and
> that is the reason why you don't see all the values appended to the
> URL. It's not because of the hidden fields. You should do the
> following:
>
> 1. Take a look at this thread which provides a useful discussion on
> the subject of scraping -http://tinyurl.com/crj792
> 2. Download and install Fiddler v2 and use it to plug into and analyze
> your HTTP request as the browser submits information from the first
> page to the second and so on. You will realize that it provides you
> with a list of parameters that are submitted on the request and that
> is what you need to replicate.
> 3. Find out what the Javascript function "submitReportRequest" does on
> your page. It is possible that it modifies the form values.
> 4. None of the hidden fields appear to transmit or upload a file. The
> value field is transmitted as a string. However, there may be other
> fields that we have not seen here, so investigate this.
> 5. Use POST requests if you don't want the full form information to be
> visible in the URL/address bar.
>
> You should follow these steps and get back to us if you need more
> information or assistance. Hope this info is helpful !

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