WebRequest for images

[TomislaW]

I need to include some pictures from other web application (written in
Java), Source of pictures are: <http://www.xy.com/bla/id/imageNumber>. I
don't know how many pictures there are So I need to read header from
WebRequest to see if it is default image or not This is my code:

int i = 0;
bool defaultImage = true;
do
{
i++;
WebRequest myWebRequest = WebRequest.Create("http://www.xy.com/bla/id/" +
i.ToString());
WebResponse myWebResponse = myWebRequest.GetResponse();
defaultImage = bool.Parse(myWebResponse.Headers["DEFAULTIMAGEUSED"]);
myWebResponse.Close();
if(!defaultImage)
Response.Write("<img src='" + myWebResponse.ResponseUri.AbsoluteUri +"'>");
}while(!defaultImage);

this is very slow and I think that my web application doing two requests for
one picture (
once when I make WebRequest in code and once when I set src of img tag in
html)

, is there any better solution?

 

[S. Justin Gengo]

Tomisla,

Here is an excerpt from an image scraper I wrote. I parse the html returned
from a web request with a regular expression to get every image on the page.

If Not Html Is Nothing Then

'---Create a regular expression to find all image uris
Dim RegEx As New
System.Text.RegularExpressions.Regex("(?:""|')([^""']+.(gif|jpg|jpeg|jpe|bmp|png|tif|tiff|swf))(?:""|')")

Dim Matches As System.Text.RegularExpressions.MatchCollection =
RegEx.Matches(Html)

'---Store the image uris found on the page in the ImageUriArrayList
For Each UriMatch As System.Text.RegularExpressions.Match In Matches

CurrentLink = UriMatch.ToString.Replace(""""c, "").Replace("'"c, "")

CurrentLink = CreateFullUri(ResponseUri.AbsoluteUri, CurrentLink)

If Not ImageUriArrayList.Contains(CurrentLink) Then

ImageUriArrayList.Add(CurrentLink)

'---Keep the page search from searching the image
LinksFound.Add(CurrentLink)

'---Up the image count to display
ImagesFoundCount += 1

End If

Next



End If

Each image link found is placed into an array of links and then a single
request for each image is made.
--
Sincerely,

S. Justin Gengo, MCP
Web Developer / Programmer

www.aboutfortunate.com

"Out of chaos comes order."
Nietzsche

 

[TomislaW]

thank you, but images are not on the same page(link)
image number one: http://www.xy.com/bla/id/1
image number two http://www.xy.com/bla/id/2
....
image number n: http://www.xy.com/bla/id/n

for one object id i don't know how much images(links) I have

Tomisla,

Here is an excerpt from an image scraper I wrote. I parse the html
returned from a web request with a regular expression to get every image
on the page.

If Not Html Is Nothing Then

'---Create a regular expression to find all image uris
Dim RegEx As New
System.Text.RegularExpressions.Regex("(?:""|')([^""']+.(gif|jpg|jpeg|jpe|bmp|png|tif|tiff|swf))(?:""|')")

Dim Matches As System.Text.RegularExpressions.MatchCollection =
RegEx.Matches(Html)

'---Store the image uris found on the page in the ImageUriArrayList
For Each UriMatch As System.Text.RegularExpressions.Match In Matches

CurrentLink = UriMatch.ToString.Replace(""""c, "").Replace("'"c, "")

CurrentLink = CreateFullUri(ResponseUri.AbsoluteUri, CurrentLink)

If Not ImageUriArrayList.Contains(CurrentLink) Then

ImageUriArrayList.Add(CurrentLink)

'---Keep the page search from searching the image
LinksFound.Add(CurrentLink)

'---Up the image count to display
ImagesFoundCount += 1

End If

Next



End If

Each image link found is placed into an array of links and then a single
request for each image is made.
--
Sincerely,

S. Justin Gengo, MCP
Web Developer / Programmer

www.aboutfortunate.com

"Out of chaos comes order."
Nietzsche

I need to include some pictures from other web application (written in
Java), Source of pictures are: <http://www.xy.com/bla/id/imageNumber>. I
don't know how many pictures there are So I need to read header from
WebRequest to see if it is default image or not This is my code:

int i = 0;
bool defaultImage = true;
do
{
i++;
WebRequest myWebRequest = WebRequest.Create("http://www.xy.com/bla/id/" +
i.ToString());
WebResponse myWebResponse = myWebRequest.GetResponse();
defaultImage = bool.Parse(myWebResponse.Headers["DEFAULTIMAGEUSED"]);
myWebResponse.Close();
if(!defaultImage)
Response.Write("<img src='" + myWebResponse.ResponseUri.AbsoluteUri
+"'>");
}while(!defaultImage);

this is very slow and I think that my web application doing two requests
for one picture (
once when I make WebRequest in code and once when I set src of img tag in
html)

, is there any better solution?

 

[S. Justin Gengo]

Tomisla,

Then a Do While may be in order how about something like this?

'---Get the response produced by the request
Dim Response As System.Net.HttpWebResponse

Response = CType(ImageWebRequest.GetResponse, System.Net.HttpWebResponse)

While Response.StatusCode = System.Net.HttpStatusCode.OK
'---Load the image

'---Get the next repsonse
Response = CType(ImageWebRequest.GetResponse,
System.Net.HttpWebResponse)
End While

'---Clean up
Response.Close()
Response = Nothing


--
Sincerely,

S. Justin Gengo, MCP
Web Developer / Programmer

www.aboutfortunate.com

"Out of chaos comes order."
Nietzsche

thank you, but images are not on the same page(link)
image number one: http://www.xy.com/bla/id/1
image number two http://www.xy.com/bla/id/2
...
image number n: http://www.xy.com/bla/id/n

for one object id i don't know how much images(links) I have

Tomisla,

Here is an excerpt from an image scraper I wrote. I parse the html
returned from a web request with a regular expression to get every image
on the page.

If Not Html Is Nothing Then

'---Create a regular expression to find all image uris
Dim RegEx As New
System.Text.RegularExpressions.Regex("(?:""|')([^""']+.(gif|jpg|jpeg|jpe|bmp|png|tif|tiff|swf))(?:""|')")

Dim Matches As System.Text.RegularExpressions.MatchCollection =
RegEx.Matches(Html)

'---Store the image uris found on the page in the ImageUriArrayList
For Each UriMatch As System.Text.RegularExpressions.Match In Matches

CurrentLink = UriMatch.ToString.Replace(""""c, "").Replace("'"c, "")

CurrentLink = CreateFullUri(ResponseUri.AbsoluteUri, CurrentLink)

If Not ImageUriArrayList.Contains(CurrentLink) Then

ImageUriArrayList.Add(CurrentLink)

'---Keep the page search from searching the image
LinksFound.Add(CurrentLink)

'---Up the image count to display
ImagesFoundCount += 1

End If

Next



End If

Each image link found is placed into an array of links and then a single
request for each image is made.
--
Sincerely,

S. Justin Gengo, MCP
Web Developer / Programmer

www.aboutfortunate.com

"Out of chaos comes order."
Nietzsche

I need to include some pictures from other web application (written in
Java), Source of pictures are: <http://www.xy.com/bla/id/imageNumber>. I
don't know how many pictures there are So I need to read header from
WebRequest to see if it is default image or not This is my code:

int i = 0;
bool defaultImage = true;
do
{
i++;
WebRequest myWebRequest = WebRequest.Create("http://www.xy.com/bla/id/"
+ i.ToString());
WebResponse myWebResponse = myWebRequest.GetResponse();
defaultImage = bool.Parse(myWebResponse.Headers["DEFAULTIMAGEUSED"]);
myWebResponse.Close();
if(!defaultImage)
Response.Write("<img src='" + myWebResponse.ResponseUri.AbsoluteUri
+"'>");
}while(!defaultImage);

this is very slow and I think that my web application doing two requests
for one picture (
once when I make WebRequest in code and once when I set src of img tag
in html)

, is there any better solution?

 

[Bruce Barker]

try a HEAD request instead of a GET. this will return the headers and not
the image data, so the request should be faster. if it doesn't work, report
a bug to your java group, should be trival to fix.

-- bruce (sqlwork.com)

 

[TomislaW]

try a HEAD request instead of a GET. this will return the headers and not
the image data, so the request should be faster. if it doesn't work,
report a bug to your java group, should be trival to fix.

-- bruce (sqlwork.com)

how to do this with c#?
I don't work with Java, my partner site is in Java

 

[Joerg Jooss]

how to do this with c#?
I don't work with Java, my partner site is in Java

I guess Bruce meant the case that the Java web application doesn't
support HEAD requests, which is very unlikely. All you need to in your
code is to set WebRequest.Method to "HEAD".

Cheers,

 

[TomislaW]

I guess Bruce meant the case that the Java web application doesn't
support HEAD requests, which is very unlikely. All you need to in your
code is to set WebRequest.Method to "HEAD".

Thanks

That was answer I was looking for