VB.Net and Web Proxy Servers and a Web Service and HTTP status 417

Question

5.00/5 (1 vote)

See more:

, +

Hi Guys

I have a VB program, lets call it AddressSearch. I have access to a 3rd party web service. I send the web service a post code, and it returns a list of valid addresses. Until recently.

Code hasn't changed, and (as far as we know) the web service hasn't been changed (do I trust the vendor?), and (as far as I know) the web proxy server hasn't been changed (do I trust my hardware manager?).

And yet when I send a valid post code from AddressSearch to the web service through the web proxy server I get the following Error Message:
System.Net.WebException: The request failed with HTTP status 417: Expectation.

If I go to the web service through my web browser (IE), through the web proxy, I get a valid list of addresses ... expected.

The VB.Net code used to get the default web proxy and default credentials (from Internet Options/Connections/LAN Settings I understand) is:

VB

If ws.Proxy Is Nothing Then
    ws.Proxy = WebRequest.DefaultWebProxy
    ws.Proxy.Credentials = System.Net.CredentialCache.DefaultCredentials
End If

where "ws" is a reference to the web service.

If I go back into Internet Options and turn off the "Use automatic configuration script", then run the same tests again, I get the following:

Send a valid post code from AddressSearch to the web service, I get back a valid list of addresses. Great!

Send an invalid post code to the web service through the web proxy server I get the following Error Message:
System.IndexOutOfRangeException: Index was outside the bounds of the array.

Through a web browser, I get a valid list of addresses.

So at first I was going to yell at the vendor, but I get a valid response from the web service via IE going through the web proxy.
Then I was going to kick the hardware manager, but again if I get a valid response from the web service via IE going through the web proxy, the web proxy isn't to blame.
I can't kick myself (just yet) as the code hasn't been altered for months.

Does it matter that my users use the AddressSearch through a terminal server session?

So now I am confused, and I need your help.

Thanks for reading!!

Simon

Posted 10-Mar-11 3:59am

SiBaggers

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Piccadilly Yum Yum · Accepted Answer · 2011-03-10T04:21:00

Solution 1

maybe this help ?

The request failed with HTTP status 417: Expectation failed[^]

Posted 10-Mar-11 4:21am

Piccadilly Yum Yum

Comments

Dylan Morley 10-Mar-11 10:31am

Yep, should do it

SiBaggers 10-Mar-11 10:36am

Thanks for that Dylan, but I'd already tried that and it didn't make any difference.

SiBaggers 10-Mar-11 10:44am

WAIT WAIT WAIT
Piccadilly & Dylan ... thanks

I had tried the code, but that made no difference. But then I tried the settings in the config file and ... eureka

Fantastic, thanks for input