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Errors trying to implement Adobe Helpx RESTful Services example
I just installed on AEM 6.1 - the example application works fine:
You stated:
it was working initially, but after uninstalling, re-installing and restarting the server
why did you un-install. I am just wondering.
The OSGi bundle for this example imported these packages:
| Imported Packages | org.apache.http,version=4.3.2 from org.apache.httpcomponents.httpcore (123) org.apache.http.client.methods,version=4.3.4 from org.apache.httpcomponents.httpclient (122) org.apache.http.conn,version=4.3.4 from org.apache.httpcomponents.httpclient (122) org.apache.http.impl.client,version=4.3.4 from org.apache.httpcomponents.httpclient (122) org.osgi.framework,version=1.8.0 from org.apache.felix.framework (0) org.osgi.service.component,version=1.3.0 from org.apache.felix.scr (31) org.slf4j,version=1.7.6 from slf4j.api (22) |
wrote...
I tested on 5.6 too and it works fine.
If you see weird OSGi message like this - install these community samples apps on a fresh instance of CQ. Looks like your other version had some sort of OSGi dependency conflicts or something else was corrupt for some reason.
Here is information on the hook rejection message:
https://issues.apache.org/jira/browse/KARAF-1728
So my advice would be to install on a fresh install and test. Remember these community articles are to teach you how to perform tasks - this one is to show you how to use Java HTTP classes to invoke 3rd party Restful services and embed that into AEM.
wrote...
I just installed on AEM 6.1 - the example application works fine:
You stated:
it was working initially, but after uninstalling, re-installing and restarting the server
why did you un-install. I am just wondering.
The OSGi bundle for this example imported these packages:
Imported Packagesorg.apache.http,version=4.3.2 from org.apache.httpcomponents.httpcore (123)
org.apache.http.client.methods,version=4.3.4 from org.apache.httpcomponents.httpclient (122)
org.apache.http.conn,version=4.3.4 from org.apache.httpcomponents.httpclient (122)
org.apache.http.impl.client,version=4.3.4 from org.apache.httpcomponents.httpclient (122)
org.osgi.framework,version=1.8.0 from org.apache.felix.framework (0)
org.osgi.service.component,version=1.3.0 from org.apache.felix.scr (31)
org.slf4j,version=1.7.6 from slf4j.api (22)
I had to reboot my computer, and when I restarted AEM 6.1, the installation would no longer work. So, I uninstalled, re-installed etc. trying to get it working again. I couldn't understand what had changed so that I started getting the HTTP error message after re-starting.
Also, please help me understand how to go about determining which classes to export and import when I create OSGI bundles, (in general). I've assumed that whenever you create a bundle, you put the classes you are providing/exposing in the service, (from the jars you're wrapping, or creating from custom development), into the "Export-package" section, and you put any other classes that the jars or your custom code is dependent on, in the "Import-package" section. Is this correct? The article said to be sure that the Export-package, and Import-package sections in the Manifest were populated, but didn't tell you what should be in there. You're saying that all I have to do is to remove the version information, but using Eclipse, I had to explicitly select the classes that I wanted to include in the Export-package, and I thought this was the way I was making the classes from the two jars I wrapped, available in the service. I wasn't sure if I needed to include the "Distance" and/or "DistanceImpl" classes in the export-package section of the jar created from the code implementing the Distance() method.
Hi
I also have checked this helpx article (https://helpx.adobe.com/experience-manager/using/restful-services.html) in my instance (AEM 6.1), it is working perfectly fine.
To answer you question "please help me understand how to go about determining which classes to export and import when I create OSGI bundles", Please find below the reference article to help you with understanding this:
//The dependencies between bundles are expressed statically in terms of packages and dynamically in terms of services. A package is familiar to Java programmers. For example, a Java program may depend on a class org.foo.X, from package org.foo, and a bundle containing that program would either need to contain org.foo.X or depend on the package org.foo. Package dependencies are specified in the bundle manifest, for example:
Import-Package: org.foo
A bundle which provides a package for use by other bundles must export the package in its manifest. For example:
Export-Package: org.foo
Coming back to the article, just follow the steps mentioned in the article,
Step 1:- Run the following Maven command:
mvn archetype:generate -DarchetypeRepository=https://repo.adobe.com/nexus/content/groups/public/ -DarchetypeGroupId=com.day.jcr.vault -DarchetypeArtifactId=multimodule-content-package-archetype -DarchetypeVersion=1.0.2 -DgroupId=com.adobe.restservice -DartifactId=restful -Dversion=1.0-SNAPSHOT -Dpackage=com.adobe.restservice -DappsFolderName=myproject -DartifactName="My Project" -DcqVersion="5.6.1" -DpackageGroup="My Company"
Step 2:- mvn eclipse:eclipse
Step 3:- Add Java files to the Maven project using Eclipse
Step 4:- Including HTTP client packages to CQ (This step is important, this is helping us to add external libs to our project. Here external jars are converted to OSGI and then installed in console which would be later used by our main component as a dependency).
How to create it
// 
Exported Packages
//
Note:-
You stated:
it was working initially, but after uninstalling, re-installing and restarting the server
I tried reproducing this behavior it is working perfectly fine.
I hope this would help you.
Thanks and Regards
Kautuk Sahni
Kautuk Sahni
wrote...
If you do not understand - we can arrange for a connect session and we will show you all of this. Let me know.
Thank you SO much for the information, and the offer to do a connect session. Fortunately, I don't need it in this instance, (so I'll take a raincheck for a future issue 
). I now have the example working in both the 5.6.1, and the 6.1 environments. The issue with the 6.1 environment, (which I simply downloaded and installed the package), had to do with the OSGI bundles not being removed when I uninstalled the package, (and tried to do a clean install). When I uninstalled the package, and then explicitly removed the two associated bundles manually, then re-installed, they both started up, ("Active"), and it works just fine.
The problem with the 5.6.1 component, (which I built myself following the step by step instructions), were simply due to not having listed all of the dependencies for the bundle in the "Import-package" section. The instructions tell you to ensure that the Import-package section is populated, but don't tell you the classes that need to be there. You have to go look in the error log file, (...AEM/author/crx-quickstart/logs/error.log), search for errors from the OSGI bundle attempting to start, and see which classes it's failing to find, (e.g. NoClassDefFoundError: org/apache/commons/logging/LogFactory). Once I got all of the dependent classes listed in the import-package, it worked just fine. I'd tried to use the automated dependency features in Eclipse, (when I built the bundle that wrapped the org.apache.httpclient jars), to give me the dependencies required by the jars I wrapped in the bundle, but it didn't list the classes that I eventually had to add to get it working. Maybe the dependency features don't work, or I'm simply still mis-understanding it a bit. In the future, I'd like an automated means of finding the dependency chain for any jars that I decide to expose/provide through a bundle, so that I can list them in the "Import.package" section in the header. How would I know that I needed to import the org.apache.commons.logging package???
wrote...
I will add a note that says it is automatically done. If it's empty - this means that Eclipse did not do its job for some reason. I am very glad you got it working.
The article tells you to "make sure that the Import-Package header is MANIFEST.MF is populated", but it doesn't tell you what to do if Eclipse doesn't populate it. How would a AEM user typically find out that he needed to import the org.apache.commons.logging package, (and other dependent packages) in the Import-Package section???
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