Web2Py Manual

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Until a few years ago, the standard interface for communication between web servers and web applications was the Common Gateway Interface CGI [ cgi ]. If the web application is written in an interpreted language, each HTTP request served by the CGI scripts starts a new instance of the interpreter.

This is slow, and it should be avoided in a production environment. Moreover, CGI can only handle simple responses. It cannot handle, for example, file streaming. In the last few years, the Python community has come together behind a new standard interface for communication between web servers and web applications written in Python. In this case, we must use Apache as a proxy and forward all incoming requests to the web2py built-in web server running for example on localhost According to the Lighttpd web site, "Lighttpd powers several popular Web 2. Its high speed IO-infrastructure allows them to scale several times better with the same hardware than with alternative web-servers".

On GAE, web applications run "in the cloud". This means that the framework completely abstracts any hardware details. The web application is automatically replicated as many times as necessary to serve all concurrent requests. Replication in this case means more than multiple threads on a single server; it also means multiple processes on different servers. GAE achieves this level of scalability by blocking write access to the file system, and all persistent information must be stored in the Google BigTable datastore or in memcache.

On non-GAE platforms, scalability is an issue that needs to be addressed, and it may require some tweaks in the web2py applications.

Web2py Manual : Enterprise Web Framework

The most common way to achieve scalability is by using multiple web servers behind a load-balancer a simple round robin, or something more sophisticated, receiving heartbeat feedback from the servers. Even if there are multiple web servers, there must be one, and only one, database server. By default, web2py uses the file system for storing sessions, error tickets, uploaded files, and the cache. This means that in the default configuration, the corresponding folders have to be shared folders. In the rest of the chapter, we consider various recipes that may provide an improvement over this naive approach, including:.

While we recommend following the first three recipes, the fourth recipe may provide an advantage mainly in the case of small files, but may be counterproductive for large files. Web2py comes with a file called anyserver. Here -l is for logging and -P is for the profiler. For information on all the command line options use "-h":. Both of these scripts should run out of the box, but every Linux installation is a bit different, so make sure you check the source code of these scripts before you run them. In the case of Ubuntu, most of what they do is explained below.

They do not implement the scalability optimizations discussed below.

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In this section, we use Ubuntu Server Edition as the reference platform. The configuration commands are very similar on other Debian-based Linux distribution, but they may differ for Fedora-based systems which uses yum instead of apt-get. You can use either 2. First, make sure all the necessary Python and Apache packages are installed by typing the following shell commands:. These steps can be performed with the following shell commands:.

When you restart Apache, it should pass all the requests to web2py without going through the Rocket wsgiserver. As documented in the handlers directory, the script you want should be moved or copied to the parent directory i. By defining this inside of the virtual host, only this virtual host can access this using WSGIProcessGroup, including any virtual host with the same server name but on a different port.

The "user" and "group" options should be set to the user who has write access to the directory where web2py was setup. You do not need to set "user" and "group" if you made the web2py installation directory writable by the default user that Apache runs as. The "display-name" option makes the process name appears in ps output as " wsgi-web2py " instead of as name of Apache web server executable. As no "processes" or "threads" options are specified, the daemon process group will have a single process with 15 threads running within that process.

python - Web2Py minimal User authentication (username only) - Stack Overflow

This is usually more than adequate for most sites and should be left as is. This is because any use of the "processes" option will cause that flag to be set to true, even a single process, and such tools expect that it be set to false. This will create five processes in the daemon process group where each process is single threaded. Normally we would just allow permission to the whole directory where the WSGI script file is located, but web2py places the WSGI script file in a directory which contains other source code, including the admin interface password. Opening up the whole directory would cause security issues, because technically Apache would be given permission to serve all the files up to any user who traversed to that directory via a mapped URL.

To avoid security problems, explicitly deny access to the contents of the directory, except for the WSGI script file, and prohibit a user from doing any overrides from a. In production it may be necessary to set the admin password programmatically. This can be done from the Bash shell with. In this case, the simplest solution is to run Apache as a proxy and have Apache deal with static files only.

The above script exposes only the "welcome" application. The script assumes there is a web2py server running on port Before restarting Apache, make sure this is the case:. In the latter case, the previously stored password is reused and the password is not stored in the shell history. The nohup commands makes sure the server does not die when you close the shell. On Ubuntu, or other Debian-based Linux distribution, edit "web2py.

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On Fedora, or any other distributions based on Fedora, edit "web2py. Nginx is a free, open-source web server that has rapidly been gaining popularity for its amazing performance. Unlike traditional servers, Nginx does not use threads. This architecture results in a small and predictable memory usage, even under heavy load.

Using Wing with web2py

Nginx is easy to configure and its configuration files and simpler and more compact than the corresponding Apache ones. Lighttpd FastCGI fcgihandler.

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You can install Lighttpd on a Ubuntu or other Debian-based Linux distribution with the following shell command:. In the config file, write something like:. As in the case of Apache, it is possible to setup Lighttpd to deal with static files directly, and to force some applications over HTTPS. Refer to the Lighttpd documentation for details. The administrative interface must be disabled when web2py runs on a shared host with FastCGI, or it will be exposed to the other users. There are times, specifically on shared hosts, when one does not have the permission to configure the Apache config files directly.

Its web interface is written in Python. In addition, there is no restart required for most of the changes. Download Cherokee [ cherokee ]. This will start web2py under FastCGI handler.

Web2Py Tutorial CRUD

By default, cherokee-admin only listens at local interface on port This is not a problem if you have full, physical access on that machine. If this is not the case, you can force it to bind to an IP address and port by using the following options:. In cherokee-admin web interface, click "info sources". Choose "Local Interpreter". Write in the following code, then click "Add New". PostgreSQL is a free and open source database which is used in demanding production environments, for example, to store the. It has very fast and solid transaction support, and provides an auto-vacuum feature that frees the administrator from most database maintenance tasks.

It is wise to run the web server s and the database server on different machines. In this case, the machines running the web servers should be connected with a secure internal physical network, or should establish SSL tunnels to securely connect with the database server. When restarting the PostgreSQL server, it should notify which port it is running on. Unless you have multiple database servers, it should be Once the database server is up and running, create a user and a database so that web2py applications can use it:.

The first of the commands will grant superuser-access to the new user, called myuser. It will prompt you for a password. Normally you use one database for each application, and multiple instances of the same application connect to the same database. It is also possible for different applications to share the same database. Task definition is done in a model file. But the initial queuing of a repeating task is most easily done from a non-exposed controller function.

By doing this in a controller rather than in a model file, you remove unnecessary database accesses that would occur on every request to your website. A non-exposed function is any controller function that has an argument, so writing something like the following in a controller e. Your application may have a need for a pre-populated database table. A simple example might be a table of color names, or the names of the months perhaps in a special format not used in Python datetime routines.

More complicated examples might include an initial inventory of parts, or the initial pages of a wiki. The simple examples might be done via db. As in the task queuing section above, this should be done using non-exposed controller functions.

nuereralami.gq Table definition for a database is done in model files, but model files are read on every request, so one-time actions should not be in the model files where they would lower the responsiveness of your site. Again, a non-exposed function is any controller function that has an argument, so writing something like the following in a controller e.