I am incredibly confused here. I've been using Google Appengine for our webserver and it's been working out great so far, but I had a request to have the webpages load without the .html extension. I've been doing some reading and see that I need to create an app.yaml file to map the url to something else? This is what I have in my file so far:
application: company-website
version: 1
runtime: java
threadsafe: true
handlers:
- url: /about
script: about.html
I've been trying to read how to do this on their documentation site but I can't seem to find anything referencing how to remove the extension and still have it point to the right html file. Can anyone help me out? Can I just do this in the appengine-web.xml file, also? It seems like I could just do it in there without creating an app.yaml file.
Any help would be appreciated. Thanks!
edit: tried some more things.. Tried moving the file I'm trying to remove the extension on to its own folder like so:
/root
-index.html
-/about
-index.html
And this was OK, when I typed my domain.com/about/ it appears to be working but when I typed domain.com/about it does not. Very frustrating.
In an ideal world we would have the option to configure a rewrite like apache's mod_rewrite in the underlying web server. Sadly it is not possible to configure a rewrite on such a level.
I searched around a bit and found that the most common answer for a rewrite is to user either UrlRewriteFilter or to wire up the servlets yourself. Both options are explained in
Catch-all URL rewrite on Google App Engine (Java)
Pretty URLs in Google App Engine
Both work in the same way and will require the app to serve static content through app engine. This will result in app engine instance hours and slower responses since all you static files move from Google's content delivery network (cdn) to your bottleneck app. The aproaches possibly also require you to deploy your static files as resource instead (How-To configure static-files and resources), at least that is how i have done this before.
These are the 'pure Java' options you have. The app.yaml approach that Josep Valls described will work in with Java on App Engine. The main question here is if the app.yaml configuration is low level enough to be a rewrite that google recognizes in its cdn, or whether you'll still burn through instance hours because all content is served through instances.
The documentation tells us:
For efficiency, App Engine stores and serves static files separately
from application files. Static files are not available in the
application's file system. If you have data files that need to be read
by the application code, the data files must be application files, and
must not be matched by a static file pattern.
Since this comes right before the section that explains how to configure the static file pattern handlers one should assume that the configuration of such handlers will not break the logic that is mentioned above - that is
stores and serves static files separately from application files
Whether this assumption is correct is an easy experiment which i shall conduct given time and report my findings here.
These are all the existing options I could find and know of. If anyone knows more on this topic, please comment / respond.
EDIT (7.12.2015)
My maven target appengine:devserver is completely oblivious to settings in the app.yaml. I'll have to experiment with this during one of the next deployment phases or use mvn gcloud:run.
... later that day:
Rewriting the URL via Servlet (like with Paul Tuckey's UrlRewriteFilter) does not work for static files. You would have to deploy the files as resource files. Static files reside somewhere else and will not be found if forwarded to by a servlet. At least that's how i understand it.
In Python and Go you can use regular expression matching in your url handlers; if Java also uses app.yaml you could probably do this:
- url: /(about|other|sections)$
static_files: \1\.html
Related
I am a beginner and self learning web development for my personal interest, and I have a general question.
I developed a Dynamic Web application in eclipse which uses index.php (or .html ; I can choose) to make a call to javascript file, the JS file calls a java servlet for some optimization and internal calculations through AJAX call, and returns back data to JS and later to the HTML form on index.php. All the paths and mappings are done on web.xml file, and everything works perfectly! The project involves some external google libraries as well, which I have included in eclipse through Build Path.
Then I installed Wordpress locally through Xampp and copied all these files (including all the java classes and external JARs) keeping the folder structure same. Here, index.php does make the call to javascript file, but for AJAX call to java it shows me network error 404. So I have 2 questions:
Does the Wordpress doesn't accept mapping through web.xml? Should I only use absolute paths? I am avoiding absolute paths since I want flexibility in moving files around and I don't know how it will work online when I upload my project somewhere.
Or is the Wordpress/ Xampp not building/ compiling Java classes and external JARs somehow like it is done in Eclipse? I have no idea how this works! I did copy all the updated class files and stuff to the wordpress folders.
Please let me know how to proceed from here, or any suggestions in things I need to learn! I am keen to use Wordpress since it will save me lot of time in writing all the page codes for my website but the java file is also integral to it since it does lot of backend work. I saw lot of comments online that wordpress and java don't go together since it being a PHP based (I actually learned PHP due to this), but it works in eclipse using these 2 languages, so I am hopeful!! So any guidance will be really appreciated!
Thank you! :D
Anang
We have this JAVA webservice that runs on tomcat 9(installed by root).
The webservice creates a generic file log for our client. The problem is only the root user can read and access the file that is being generated.
My question is can I change the output file to be readable for all users by default? (without using chmod everytime the file is generated)
Should it be on code level or configure it on linux?
I have read about this https://docs.oracle.com/javase/tutorial/essential/io/file.html.
But one of our old redhat servers dont have a code level config on its webservice and its working fine.
Thanks
You should not be looking at this from a "java io" side of things.
This is a user permission problem. In other words: probably your tomcat servers shouldn't be running as root in the very first place.
Consider creating a special user that is used to run your tomcat instance. Here you can find guidance how you could do that for an Ubuntu system. And your favorite search engine will for sure know similar links for your favorite Linux distribution, too.
That might also be better from a security perspective: do you really want that people attacking your tomcat ... end up being root on your system if they succeed?!
Long story short: your problem is not some java code within tomcat that writes files; and then other users on your system being unable to access those files. Your problem is that your tomcat service is running as root! Fix the later; and your "initial" problem will be fixed, too.
Final word of warning though: I am not saying that it is easy to change the user setup for you. Maybe it is; but especially if your setup is using "root" for a long time, then there is a certain chance that other things you put in place rely on "being root". So, "not being root" is the right direction; but it might be a painful path to get there, from where you are now.
I am using GWT 2.0.3 with ext version.When I run the application its take some time to load.As much as I know It take time to load some JS file (Not sure about it).For slow internet connection it wiil take more time.
I want to know what exactly GWT application do while loading.If it is loading some JS file the is there ant way to reudce loading time by dividing JS file or by nay other way?
Thanks in advance
When a GWT application loads, it loads all js files contained in your html host page, what means everything client side related is loaded.
To optimize this GWT introduced code splitting some time ago. You can check it here. The basic idea is to divide your application in logical parts, when a user wants to access to another part, its loaded on demand.
To speed up web app loading time, indeed split points are a first step.
But check as well this tool:
http://pagespeed.googlelabs.com
Slowness can also come from uncompressed pictures for instance.
Also, when you compile your GWT app, ensure you use "OBFUSCATED" mode for your compiled javascript, which makes it significantly smaller.
http://code.google.com/webtoolkit/doc/1.6/FAQ_DebuggingAndCompiling.html#Why_is_my_GWT-generated_JavaScript_gibberish?
Now if you are using Apache HTTPD as web server, Google has released a wonderful Apache module that implements web app best practices out of the box:
http://code.google.com/p/modpagespeed/
I have developed a command-line (read: no GUI) Java application which crunches through numbers based on a given dataset and a series of parameters; and spits out a series of HTML files as resultant reports. These reports hold a large amount of data in tables, so in order to give the users a easy and quick overview of the results, I utilized the JUNG2 library and created a nice graph.
Here's where it gets interesting; since I would like the graph to be interactive it should be deployed after the application has run and files are generated, whenever the user wants to view the reports. I decided to go with an applet based deployment, however I am not too happy with the current setup due to the following reasons:
I want to make the software as simple to use as possible (my users won't be tech-savvy, and even tech-intimidated in most cases). I would really like to distribute one JAR only, which forced me to put the applet with everything else it needs in a package in the same JAR as the main application.
The applet and the main application need to communicate the results, so I create a xML-based report which is used to hold information. As long as the files are on a local machine and are not moved around it all works fine. Unfortunately I also need the files to be moved around. A user should be able to take the "results" folder to a USB stick, go anywhere plug the stick to another computer and be able to use the report as he/she likes.
For the time being the applets are implemented with the following html code:
<applet code="package.myapp.visualization.GraphApplet.class"
codebase="file:/home/user/myApp"
archive="myApp-0.2.6-r28.jar"
width="750" height="750">
<param name=input value="results/test_name/results.fxml">
</applet>
As you can see this applet will not work if the parent folder is moved to another location.
As far as I know I have a couple of alternatives:
a) Change codebase to point to an URL on our webserver where I could put the jar file. This however creates the problem with permissions, as the applet will not be able to read the results file. Alternative is to upload the results file to the server when the user wants to visualize the graph, although I am not sure if that's a good option due to server security and also if it could be made so that upload happens automatically without bothering the user.
b) I can use a relative path on the codebase attribute, but then the whole folder hierarchy needs to be intact upon copy. This could be a last resort, if I cant come up with a better way to do it.
c) change the deployment method (would like to avoid this alternative to not spend more time on the development phase)
Any ideas? Am I missing something? How could I tackle this problem?
Thanks,
I'm not sure I entirely understand your use-case, but from what I do understand, I would suggest this:
Dump the applet for an application launched using Java Web Start. Have the JNLP file declare a file association for the fxml file type. When the user double clicks an fxml file, it will be passed as an argument to the main(String[]) of the JWS application.
A sand-boxed JWS application can gain access to resources on the local file system using the JNLP API. Here is my demo. of the JNLP API file services.
We have to make a Java application demo available on Internet using JWS. It goes pretty well; all that's missing is making working directory files available for the application.
We know about the getResource() way... The problem is that we have different plugins for the same application and each one require different files (and often different versions of the same files) in their working directory to work properly. So we just change the working directory when we want the application to have a different behavior.
Currently, the demo is packaged in a signed jar file and it loads correctly until it requires a file from the working directory. Obviously, the Internet users of this demo don't have the files ready. We need a way to make these files available to the WebStart application (read/write access) in its working directory.
We've thought of some things, like having the application download the files itself when it starts, or package them in the jar and extract them on startup.
Looking for advices and/or new ideas. I'll continue working on this... I'll update if I ever find something reliable.
Thank you very much!
I said I would share what I found in my research for something that would fit my needs. Here's what I have so far.
I have found that the concept of current working directory (CWD) does not really make sense in the context of a Java Web Start (JWS) application. This had for effect that I stopped trying to find the CWD of a JWS and started looking for other options.
I have found that (no, I didn't know that) you can refer (using getResource()) to a file in the root directory of a JAR file by simply adding a '/' in front of its name. ("/log4j.properties", for example.) The impact of this is that I can now take any file which is only referred to in a read-only manner in the root of that JAR file (which is really only a ZIP file). You can refer to any file in the root of the JAR file using AnyClass.class.getResourceAsStream. That rules out the problem with read-only files required to run the application, at the cost of a switch in the code telling whether the application is run from a valid CWD or from a JWS context. (You can very simply set a property in the JNLP file of the JWS application and check if that property is set or not to know where to look for the file.)
For write-only files (log files in my case), I used the property , adding a directory with the name of the application: <user.home>/.appname and added log files to it.
Read/write files (which I don't have in my case) would probably simply go at the same place than write-only files. The software could deal with uploading them somewhere if needed, once modified, I guess.
That's the way I deal with the problem for now.
Note there is a service you can explicitly ask for, to get file access to the computer (unless you go all the way and ask for full access (which requires signed jar files)).
Then you need to determine where these files need to go - basically you have no idea what is where and whether you may actually write anywhere. You can create tmp-files but those go away.
Would a file system abstraction talking to the JNLP-server do so you store the users data on the server?