Paul of onfocus.com fame (and the fabulous SnapGallery tool) wrote an article for the O’Reilly Network recently that (I think) was an excerpt of his recently released book “Amazon Hacks“. Anyway, he shows how you can check to see if an image exists on amazon.com using ASP, Perl, and PHP and I thought it would be fun to show how to do the same thing in Java, C# and ColdFusion. His examples were all functions of the form:

Function hasImage(imageUrl)

so I’m following that style. In Java you’d end up with something like this:

public static boolean hasImage(String url) {
boolean result = false;
  try {
    URL iurl = new URL(url);
    HttpURLConnection uc = (HttpURLConnection)iurl.openConnection();
    uc.connect();
    if (uc.getContentType().equalsIgnoreCase("image/jpeg")) {
      result = true;
    }
    uc.disconnect();
  } catch (Exception e) {
  }
  return result;
}

In C#, almost the exact same thing:

public static Boolean HasImage(String url) {
  Boolean result = false;
  try {
    HttpWebRequest webreq = (HttpWebRequest)WebRequest.Create(url);
    WebResponse res = webreq.GetResponse();
    if (res.ContentType == "image/jpeg") {
      result = true;
    }
    response.Close();
  } catch {
  }
  return result;
}

and then in ColdFusion:

<cffunction name="hasImage" returntype="boolean" output="no">
  <cfargument name="imageUrl" type="string" required="yes">
  <cfhttp url="#imageURL#" method="GET">
  <cfif cfhttp.responseHeader["Content-Type"] EQ "image/jpeg">
    <cfreturn true>
  <cfelse>
    <cfreturn false>
  </cfif>
</cffunction>

The full source for all these examples are available:

· Amazon.java
· Amazon.cs
· amazon.cfm

Enjoy!