Picturebox, Image.FromStrea m, WebRequest - Doesn't allways work

[Mads Aggerholm]

Hello Sirs

I hope you can give me a hint to this little problem.

The thing is, I have for a lang time enjoyed the comics on www.washintonpost.com,
and I allways start the day by going to their homepage.

One day, I thought: Why not just make a little program in C#, that
just shows me the .gif-picture of the strip?
And so I did. Or, more correctly, I tried to do.

Actually, it's quite simple. I want to show the strip of "Non
Sequitur" from the 30. of may 2008.
It can be seen directly in a browser, using this link:

http://wpcomics.washingtonpost.com/c...nq/2008/05/30/

Showing "Properties " thell me, the link directly to the .gif-file is
this:

http://wpcomics.washingtonpost.com/f...0/nq080530.gif

The strip can be viewed in a picturebox this way:

picturebox1.Ima ge = Image.FromStrea m(WebRequest.Cr eate("http://
wpcomics.washin gtonpost.com/feature/08/05/30/
nq080530.gif"). GetResponse().G etResponseStrea m());

If I want another strip from another date, I just change the date-part
of the url.

So far, so good.

However, I'd like to see "Hagar the Horrible" too. Browser link to the
same date is:

http://www.washingtonpost.com/wp-srv...&date=20080530

But here starts the problem: "Properties " on the strip is:

http://est.rbma.com/content/Hagar_Th...?date=20080530

Directly in a browser, it works fine.
But using it in a picturebox does not!

What can I do to make this work??
Any constructive input is welcome!

(It _should_ be possible! A friend told me once, that anything other
programs can do, I can do too in C#.)

Sincerely / Best regards
Mads Aggerholm

[Peter Duniho]

On Mon, 02 Jun 2008 11:01:09 -0700, Mads Aggerholm
<ma************ @gmail.comwrote :

[...]
But here starts the problem: "Properties " on the strip is:

http://est.rbma.com/content/Hagar_Th...?date=20080530

Directly in a browser, it works fine.
But using it in a picturebox does not!

Define "does not". What, exactly, doesn't work?

What can I do to make this work??
Any constructive input is welcome!

(It _should_ be possible! A friend told me once, that anything other
programs can do, I can do too in C#.)

I haven't examined this particular scenario closely. However, your
friend's advice can only be taken so far.

In particular, your C# program may not be doing _exactly_ what another
program is doing. It _could_, but it probably isn't.

Some web servers are configured so that certain content is retrievable
only in the context of the original source page. So, retrievals that
occur in a context that looks to the server like a web browser is getting
the data will work, while others will not. The web server will
intentially refuse to provide the data in the other cases.

You didn't bother to describe any specifics about what's not working, so
it's impossible for me to say for sure that this is going on. But if it
is, you'll have to make sure that your program retrieves the data in
exactly the same way that a web browser would (getting the original page,
setting the "referrer" for the graphics, etc.). The simplest way to do
this would be to run a network monitor program (the Wireshark program
might be useful in this respect) to look at what data is sent and received
by your web browser when you look at the comic in your web browser.

Of course, it's also possible that your problem is something entirely
different. It's really not possible to say without more details from
you. Very specific information as to what your code is doing and how it
fails would be the minimum, and the best explanation would include a
concise-but-complete code sample that demonstrates the issue.

Pete

[Ignacio Machin ( .NET/ C# MVP )]

http://est.rbma.com/content/Hagar_Th...?date=20080530

Directly in a browser, it works fine.
But using it in a picturebox does not!

What can I do to make this work??

Youi have to see what the above URL return, it might return a webpage
with only the image, but a webpage nevertheless. Because of that your
code does not work
I cannot check it now as that website is blocked by my company firewall

[parez]

On Jun 2, 2:01 pm, Mads Aggerholm <mads.aggerh... @gmail.comwrote :

Hello Sirs

I hope you can give me a hint to this little problem.

The thing is, I have for a lang time enjoyed the comics onwww.washinton post.com,
and I allways start the day by going to their homepage.

One day, I thought: Why not just make a little program in C#, that
just shows me the .gif-picture of the strip?
And so I did. Or, more correctly, I tried to do.

Actually, it's quite simple. I want to show the strip of "Non
Sequitur" from the 30. of may 2008.
It can be seen directly in a browser, using this link:

http://wpcomics.washingtonpost.com/c...nq/2008/05/30/

Showing "Properties " thell me, the link directly to the .gif-file is
this:

http://wpcomics.washingtonpost.com/f...0/nq080530.gif

The strip can be viewed in a picturebox this way:

picturebox1.Ima ge = Image.FromStrea m(WebRequest.Cr eate("http://
wpcomics.washin gtonpost.com/feature/08/05/30/
nq080530.gif"). GetResponse().G etResponseStrea m());

If I want another strip from another date, I just change the date-part
of the url.

So far, so good.

However, I'd like to see "Hagar the Horrible" too. Browser link to the
same date is:

http://www.washingtonpost.com/wp-srv...cs/king.html?n...

But here starts the problem: "Properties " on the strip is:

http://est.rbma.com/content/Hagar_Th...?date=20080530

Directly in a browser, it works fine.
But using it in a picturebox does not!

What can I do to make this work??
Any constructive input is welcome!

(It _should_ be possible! A friend told me once, that anything other
programs can do, I can do too in C#.)

Sincerely / Best regards
Mads Aggerholm

Try setting the User-agent in the web request header. if that does
not work then use fiddler and see what your browser sends to the site
and you send the same info from you web request.

[Mads Aggerholm]

Hi Pete, thanks for the quick answer.

On 2 Jun., 20:19, "Peter Duniho" <NpOeStPe...@nn owslpianmk.comw rote:

On Mon, 02 Jun 2008 11:01:09 -0700, Mads Aggerholm *

<mads.aggerh... @gmail.comwrote :

[...]
But here starts the problem: "Properties " on the strip is:

http://est.rbma.com/content/Hagar_Th...?date=20080530

Directly in a browser, it works fine.
But using it in a picturebox does not!

Define "does not". *What, exactly, doesn't work?

It actually comes up with a little bitmap image in my picturebox
(that's also standard like if I try a date that doesn't exist) saying:
"Content Currently Unavailable".

I am afraid I can not explain it any better.

You didn't bother to describe any specifics about what's not working, so *

Sorry about that.
Actually I have made it very simple:
I've made a C#-form, with a picturebox in it.
The code is just this:

picturebox1.Ima ge = Image.FromStrea m(WebRequest.Cr eate("http://
est.rbma.com/content/Hagar_The_Horri ble?
date=20080530") .GetResponse(). GetResponseStre am());

And I get the failure-bitmap.

When I change the code to this:

picturebox1.Ima ge = Image.FromStrea m(WebRequest.Cr eate("http://
wpcomics.washin gtonpost.com/feature/08/05/30/
nq080530.gif"). GetResponse().G etResponseStrea m());

the result is the comic strip in the picturebox - no problems.

it's impossible for me to say for sure that this is going on. *But if it*
is, you'll have to make sure that your program retrieves the data in *
exactly the same way that a web browser would (getting the original page, *
setting the "referrer" for the graphics, etc.). *The simplest way to do *
this would be to run a network monitor program (the Wireshark program *
might be useful in this respect) to look at what data is sent and received*
by your web browser when you look at the comic in your web browser.

I'll give that a try.
Thanks for your input, Pete.

Sincerely / Best regards
Mads Aggerholm

[Peter Duniho]

On Mon, 02 Jun 2008 11:38:56 -0700, Ignacio Machin ( .NET/ C# MVP )
<ig************ @gmail.comwrote :

>http://est.rbma.com/content/Hagar_Th...?date=20080530

Directly in a browser, it works fine.
But using it in a picturebox does not!

What can I do to make this work??

Youi have to see what the above URL return, it might return a webpage
with only the image, but a webpage nevertheless. Because of that your
code does not work
I cannot check it now as that website is blocked by my company firewall

For what it's worth, I just tried the link, and the server redirected to
this URL: http://est.rbma.com/content_server/noreferer.gif

That suggests that my previous guess was reasonably accurate: the server
is actively rejecting the request, because it's not being made in a way
that appears to come from a proper browser implementation in which the
original source link is hosted.

Ironically, if the OP's program had more completely handled the HTTP
protocol correctly, it would have received a GIF image with a very
specific error message in it. :) I would have thought that the
HttpRequest class would deal with this automatically, so maybe the OP is
using some lower-level class and failing to handle the HTTP stuff
appropriately. Of course, without a code sample, there's no way to know..

Pete

[parez]

On Jun 2, 2:47 pm, parez <psaw...@gmail. comwrote:

On Jun 2, 2:01 pm, Mads Aggerholm <mads.aggerh... @gmail.comwrote :

Hello Sirs

I hope you can give me a hint to this little problem.

The thing is, I have for a lang time enjoyed the comics onwww.washinton post.com,
and I allways start the day by going to their homepage.

One day, I thought: Why not just make a little program in C#, that
just shows me the .gif-picture of the strip?
And so I did. Or, more correctly, I tried to do.

Actually, it's quite simple. I want to show the strip of "Non
Sequitur" from the 30. of may 2008.
It can be seen directly in a browser, using this link:

http://wpcomics.washingtonpost.com/c...nq/2008/05/30/

Showing "Properties " thell me, the link directly to the .gif-file is
this:

http://wpcomics.washingtonpost.com/f...0/nq080530.gif

The strip can be viewed in a picturebox this way:

picturebox1.Ima ge = Image.FromStrea m(WebRequest.Cr eate("http://
wpcomics.washin gtonpost.com/feature/08/05/30/
nq080530.gif"). GetResponse().G etResponseStrea m());

If I want another strip from another date, I just change the date-part
of the url.

So far, so good.

However, I'd like to see "Hagar the Horrible" too. Browser link to the
same date is:

http://www.washingtonpost.com/wp-srv...cs/king.html?n...

But here starts the problem: "Properties " on the strip is:

http://est.rbma.com/content/Hagar_Th...?date=20080530

Directly in a browser, it works fine.
But using it in a picturebox does not!

What can I do to make this work??
Any constructive input is welcome!

(It _should_ be possible! A friend told me once, that anything other
programs can do, I can do too in C#.)

Sincerely / Best regards
Mads Aggerholm

Try setting the User-agent in the web request header. if that does
not work then use fiddler and see what your browser sends to the site
and you send the same info from you web request.

I tried going to http://est.rbma.com/content/Hagar_Th...?date=20080530
and i got an image which said no referer.

so i created an html page with that image as the source and opened
it and it worked.

which means that the image server is only checking for a referrer. so
if you change your code

HttpWebRequest request = (HttpWebRequest )WebRequest.Cre ate("http://
est.rbma.com/content/Hagar_The_Horri ble?date=200805 30");
request .Referer="Somec rap.com";

it mite work....

[Peter Duniho]

On Mon, 02 Jun 2008 11:57:33 -0700, parez <ps*****@gmail. comwrote:

I tried going to
http://est.rbma.com/content/Hagar_Th...?date=20080530
and i got an image which said no referer.

so i created an html page with that image as the source and opened
it and it worked.

which means that the image server is only checking for a referrer. so
if you change your code

HttpWebRequest request = (HttpWebRequest )WebRequest.Cre ate("http://
est.rbma.com/content/Hagar_The_Horri ble?date=200805 30");
request .Referer="Somec rap.com";

it mite work....

I find it interesting that _any_ referrer is sufficient. Usually web
sites check the referrer to make sure it's actually their own web page
(prevents hijacking/embedding content in a non-hosted page).

Anyway, to the OP: I would guess that the suggestion from "parez" will in
fact solve your problem.

Pete

[parez]

On Jun 2, 3:06 pm, "Peter Duniho" <NpOeStPe...@nn owslpianmk.com>
wrote:

On Mon, 02 Jun 2008 11:57:33 -0700, parez <psaw...@gmail. comwrote:

I tried going to
http://est.rbma.com/content/Hagar_Th...?date=20080530
and i got an image which said no referer.

so i created an html page with that image as the source and opened
it and it worked.

which means that the image server is only checking for a referrer. so
if you change your code

HttpWebRequest request = (HttpWebRequest )WebRequest.Cre ate("http://
est.rbma.com/content/Hagar_The_Horri ble?date=200805 30");

request .Referer="Somec rap.com";

it mite work....

I find it interesting that _any_ referrer is sufficient. Usually web
sites check the referrer to make sure it's actually their own web page
(prevents hijacking/embedding content in a non-hosted page).

Anyway, to the OP: I would guess that the suggestion from "parez" will in
fact solve your problem.

Pete

Well.. actually i tried that again. .i got no referer image again. I
must have got a cached imaged when i ran it locally from desktop.

HttpWebRequest request = (HttpWebRequest )WebRequest.Cre ate("http://
est.rbma.com/content/Hagar_The_Horri ble?date=200805 30");

request .Referer="Somec rap.com";

so instead of somecrap.com OP (i dont know what that means) will have
to use washtingtonpost .com

[Peter Duniho]

On Mon, 02 Jun 2008 12:30:06 -0700, parez <ps*****@gmail. comwrote:

Well.. actually i tried that again. .i got no referer image again. I
must have got a cached imaged when i ran it locally from desktop.

Ah. That makes more sense, and is consistent with how web servers usually
do it. :)

HttpWebRequest request = (HttpWebRequest )WebRequest.Cre ate("http://
est.rbma.com/content/Hagar_The_Horri ble?date=200805 30");

request .Referer="Somec rap.com";

so instead of somecrap.com OP (i dont know what that means) will have
to use washtingtonpost .com

"OP" is "original poster". Shorthand way of writing "that guy who started
all this" :).

Anyway, yes...the program will have to set the referrer field correctly.
It may be sufficient to just use the domain name, or it may be required to
use the actual URL for the web page that would normally host the content,
depending on what the web server is doing specifically.

Personally, it's my opinion that when one starts impersonating a web page,
they are getting into a gray area with respect to content/copyright
ethics. The web server owner is clearly specifically interested in making
sure that when you look at the comic, you do so in a particular context.
When you impersonate that context, you break the implied contract with the
content producer.

From the content producer's point of view, that contract may involve
ensuring that advertising or other contextual things that they deem
important or financially necessary are included. If you as the viewer
aren't willing to abide by that contract, then you're basically saying you
don't approve of the "sale", and thus shouldn't be "buying" (that is, just
don't read the comic).

As far as I know, this is not technically illegal per se. But it
definitely seems a little "wrong" to me. From an implementation point of
view, this could be avoided by just using the WebBrowser control and
displaying the entire original page rather than just the comic. That
would also automatically fix the "referrer" issue. :)

Pete