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At line 10 added 64 lines.
#Need to calculate message signature using crypto and base64 algorithm
#Need to set Http "Date" header using this format "EEE, dd MMM yyyy HH:mm:ss "
#Need to dynamically do "Get/Put/Delete/Head" operations on dynamic URLs, currently BPEL only allow dynamic URL, but not dynamic Http Verb.
!Creating a Sample Project using BPEL as orchestration
AmazonWS REST security mechanism is a little different than Google's REST security mechanism. Google requires user to do a POST operation first using username/password, and returns a security token to be used for subsequent Http requests. AmazonWS security is different. Amazon pre-issue user a pair of accessKeyId/secretyAccessKey, and for every request, user needs to put in the Http header the "Authorization" header. This header is calculated using this formula:
{{{
Authorization = "AWS" + " " + AWSAccessKeyId + ":" + Signature;
Signature = Base64( HMAC-SHA1( UTF-8-Encoding-Of( StringToSign ) ) );
StringToSign = HTTP-Verb + "\n" +
Content-MD5 + "\n" +
Content-Type + "\n" +
Date + "\n" +
CanonicalizedAmzHeaders +
CanonicalizedResource;
CanonicalizedResource = [ "/" + Bucket ] +
<HTTP-Request-URI, from the protocol name up to the query string> +
[ sub-resource, if present. For example "?acl", "?location", "?logging", or "?torrent"];
CanonicalizedAmzHeaders = <described below>
}}}
Another requirement is that "Date" header should always be set, and should be in a compliant format such as "EEE, dd MMM yyyy HH:mm:ss ".
The above two items are easy to do in Java, but not easy to do in BPEL, thus in the sample project we are creating, we use a EJB webservice as a helper library for BPEL to accomplish these two tasks.
See Figures below:
[amazon1.png]
[amazon2.png]
Basically, the flow sequence is as follows"
#BPEL process is triggered by a HTTP client via HTTPBC
#BPEL calls EJB-WS to ask for the current Date, and saves it in a variable
#BPEL calls EJB-WS to calculate the message signature of this request, and saves it in a variable
#BPEL use HTTPBC to do a GET operation on a URL, populating all the required Http headers
#BPEL returns the GET response body to the HTTP client
See picture below on how to populate the HTTP headers in BPEL mapper:
[amazon3.png]
To see how the sample project is built, download it from [amazonprojects.zip]. Note: to run it you have to replace the "secretAccessKey" in the BPEL file with your own secretAccessKey.
!POST/PUT/DELETE/HEAD
*POST: as described above, POST operation is not really used in AmazonWS, PUT is the equivalent of POST here.
*PUT: it is not currently supported by HTTPBC. It is supported by JAXWS, however, there seems to be a few problems with content-types, see issue tracked at bottom of the page.
*DELETE: it is not currently supported by HTTPBC.
*HEAD: it is not currently supported by HTTPBC.
!Issues filed:
[https://jax-ws.dev.java.net/issues/show_bug.cgi?id=657]
G'day, Anonymous Guest

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This page (revision-2) was last changed on 06-Nov-08 17:41 PM, -0800 by Edward Chou