标签归档：cgi

知识问答

普通英语的WSGI和CGI是什么？

问题：普通英语的WSGI和CGI是什么？

每次阅读WSGI或CGI时，我都会感到畏缩。我尝试过阅读它，但没有任何卡住。

普通英语到底是什么？

它只是将请求通过管道传输到终端并重定向输出吗？

点击查看英文原文

Every time I read either WSGI or CGI I cringe. I’ve tried reading on it before but nothing really has stuck.

What is it really in plain English?

Does it just pipe requests to a terminal and redirect the output?

回答 0

WSGI在Web服务器启动时（作为Web服务器进程的一部分（嵌入式模式）或作为单独的进程（守护程序模式））运行Python解释器，并将脚本加载到其中。每个请求都会导致调用脚本中的特定功能，并将请求环境作为参数传递给该功能。

CGI将脚本作为每个请求的单独进程运行，并使用环境变量，stdin和stdout与之“通信”。

点击查看英文原文

WSGI runs the Python interpreter on web server start, either as part of the web server process (embedded mode) or as a separate process (daemon mode), and loads the script into it. Each request results in a specific function in the script being called, with the request environment passed as arguments to the function.

CGI runs the script as a separate process each request and uses environment variables, stdin, and stdout to “communicate” with it.

回答 1

从完全后退的角度来看，Blankman，这是我的Web服务网关接口的“简介页”：

第一部分：网络服务器

Web服务器提供响应。他们坐在那里，耐心等待，然后突然没有任何警告：

  • 客户端进程发送请求。客户端进程可以是Web服务器，机器人，移动应用程序等。简直就是“客户”
  • Web服务器收到此请求
  • 故意咕umble各种事情发生（见下文）
  • Web服务器将某些内容发送回客户端
  • Web服务器再次坐在附近

Web服务器（至少是更好的服务器）在这方面非常擅长。他们根据需求扩展和缩减处理，通过可靠的网络可靠地与最薄弱的客户进行对话，而我们永远不必担心。他们只是继续服役。

这就是我的观点：Web服务器就是：服务器。他们对内容一无所知，对用户一无所知，实际上除了如何耐心等待和可靠答复外，一无所知。

您选择的Web服务器应该反映您的交付偏好，而不是您的软件。您的网络服务器应负责服务，而不是处理或逻辑事务。

第二部分：（PYTHON）软件

软件不存在。软件仅在执行时存在。当软件在其环境中发生意外更改（文件不在期望的位置，重命名参数等）时，软件并不适应。尽管优化应该是设计的中心原则（当然），但是软件本身并不能优化。开发人员乐观。软件执行。软件会执行上面“故意含糊不清”部分中的所有内容。可以是任何东西。

您对软件的选择或设计应反映您的应用程序，功能的选择，而不是Web服务器的选择。

这是将语言“编译”到Web服务器的传统方法变得很痛苦的地方。您最终将代码放入应用程序中以应对物理服务器环境，或者至少被迫选择一个适当的“包装”库以在运行时包括在内，从而使跨Web服务器具有统一性的错觉。

那么WSGI是什么？

那么，最后，WSGI是什么？WSGI是一套规则，分为两部分。编写它们的方式可以将它们集成到任何欢迎集成的环境中。

为Web服务器端编写的第一部分说：“好吧，如果您要处理WSGI应用程序，则这是该软件在加载时的思考方式。这是您必须为应用程序提供的内容，这里是您可以期望每个应用程序具有的界面（布局）。此外，如果出现任何问题，这是应用程序的思维方式以及期望行为的方式。”

为Python应用程序软件编写的第二部分说：“好吧，如果您要处理WSGI服务器，这是服务器与您联系时的思考方式。这是您必须向服务器提供的东西，以及这是您可以期望每台服务器都具有的接口（布局）。此外，如果出现任何问题，这是您的行为方式，也应该告诉服务器。”

因此，有了它-服务器将成为服务器，软件将成为软件，这是它们可以很好地相处的一种方式，而不必为彼此的细节留出余地。这是WSGI。

mod_wsgi的，而另一方面，是Apache的一个插件，让它跟WSGI兼容的软件，换句话说，mod_wsgi的是一个实现 -在Apache中-上面的规则手册第一部分的规则。

至于CGI ….问其他人:-)

点击查看英文原文

From a totally step-back point of view, Blankman, here is my “Intro Page” for Web Services Gateway Interface:

PART ONE: WEB SERVERS

Web servers serve up responses. They sit around, waiting patiently, and then with no warning at all, suddenly:

  • a client process sends a request. The client process could be a web server, a bot, a mobile app, whatever. It is simply “the client”
  • the web server receives this request
  • deliberate mumble various things happen (see below)
  • The web server sends back something to the client
  • web server sits around again

Web servers (at least, the better ones) are very VERY good at this. They scale up and down processing depending on demand, they reliably hold conversations with the flakiest of clients over really cruddy networks and we never really have to worry about it. They just keep on serving.

This is my point: web servers are just that: servers. They know nothing about content, nothing about users, nothing in fact other than how to wait a lot and reply reliably.

Your choice of web server should reflect your delivery preference, not your software. Your web server should be in charge of serving, not processing or logical stuff.

PART TWO: (PYTHON) SOFTWARE

Software does not sit around. Software only exists at execution time. Software is not terribly accommodating when it comes to unexpected changes in its environment (files not being where it expects, parameters being renamed etc). Although optimisation should be a central tenet of your design (of course), software itself does not optimise. Developers optimise. Software executes. Software does all the stuff in the ‘deliberate mumble’ section above. Could be anything.

Your choice or design of software should reflect your application, your choice of functionality, and not your choice of web server.

This is where the traditional method of “compiling in” languages to web servers becomes painful. You end up putting code in your application to cope with the physical server environment or, at least, being forced to choose an appropriate ‘wrapper’ library to include at runtime, to give the illusion of uniformity across web servers.

SO WHAT IS WSGI?

So, at last, what is WSGI? WSGI is a set of rules, written in two halves. They are written in such a way that they can be integrated into any environment that welcomes integration.

The first part, written for the web server side, says “OK, if you want to deal with a WSGI application, here’s how the software will be thinking when it loads. Here are the things you must make available to the application, and here is the interface (layout) that you can expect every application to have. Moreover, if anything goes wrong, here’s how the app will be thinking and how you can expect it to behave.”

The second part, written for the Python application software, says “OK, if you want to deal with a WSGI server, here’s how the server will be thinking when it contacts you. Here are the things you must make available to the server, and here is the interface (layout) that you can expect every server to have. Moreover, if anything goes wrong, here’s how you should behave and here’s what you should tell the server.”

So there you have it – servers will be servers and software will be software, and here’s a way they can get along just great without one having to make any allowances for the specifics of the other. This is WSGI.

mod_wsgi, on the other hand, is a plugin for Apache that lets it talk to WSGI-compliant software, in other words, mod_wsgi is an implementation – in Apache – of the rules of part one of the rulebook above.

As for CGI…. ask someone else :-)

回答 2

如果您不清楚这个领域中的所有术语，并且让我们面对现实，那是一个令人困惑的首字母缩写词，那么还有一个很好的背景阅读器，以官方的Python HOWTO形式提供，它讨论了CGI，FastCGI，WSGI等。上。希望我先读。

点击查看英文原文

If you are unclear on all the terms in this space, and let’s face it, it’s a confusing acronym-laden one, there’s also a good background reader in the form of an official python HOWTO which discusses CGI vs. FastCGI vs. WSGI and so on. I wish I’d read it first.

回答 3

CGI和WSGI都定义了标准接口，程序可以使用这些标准接口来处理Web请求。CGI接口的级别低于WSGI，它涉及服务器设置环境变量，该环境变量包含HTTP请求中的数据，程序返回的格式类似于裸HTTP服务器响应。

另一方面，WSGI是特定于Python的更高级别的接口，它使程序员可以编写与服务器无关的应用程序，并且可以将其包装在其他WSGI应用程序（中间件）中。

点击查看英文原文

Both CGI and WSGI define standard interfaces that programs can use to handle web requests. The CGI interface is at a lower level than WSGI, and involves the server setting up environment variables containing the data from the HTTP request, with the program returning something formatted pretty much like a bare HTTP server response.

WSGI, on the other hand, is a Python-specific, slightly higher-level interface that allows programmers to write applications that are server-agnostic and which can be wrapped in other WSGI applications (middleware).

知识问答

Python Web框架，WSGI和CGI如何结合在一起

问题：Python Web框架，WSGI和CGI如何结合在一起

我有一个Bluehost帐户，可以在其中运行Python脚本作为CGI。我猜这是最简单的CGI，因为要运行，我必须在中定义以下内容.htaccess：

Options +ExecCGI
AddType text/html py
AddHandler cgi-script .py

现在，每当我使用Python查找Web编程时，我都会听到很多关于WSGI以及大多数框架如何使用它的知识。但是我只是不明白它们之间的关系如何，特别是当我的Web服务器（在主机上运行Apache）并且没有我真正可以使用的东西（定义.htaccess命令除外）时尤其如此。

WSGI，CGI和框架如何连接？我想在基本的CGI配置上运行Web框架（例如web.py或CherryPy），该怎么办？如何安装WSGI支持？

点击查看英文原文

I have a Bluehost account where I can run Python scripts as CGI. I guess it’s the simplest CGI, because to run I have to define the following in .htaccess:

Options +ExecCGI
AddType text/html py
AddHandler cgi-script .py

Now, whenever I look up web programming with Python, I hear a lot about WSGI and how most frameworks use it. But I just don’t understand how it all fits together, especially when my web server is given (Apache running at a host’s machine) and not something I can really play with (except defining .htaccess commands).

How are WSGI, CGI, and the frameworks all connected? What do I need to know, install, and do if I want to run a web framework (say web.py or CherryPy) on my basic CGI configuration? How to install WSGI support?

回答 0

WSGI，CGI和框架如何连接？

Apache侦听端口80。它获取HTTP请求。它解析请求以找到一种响应方式。Apache有很多可供选择的响应方式。一种响应方式是使用CGI运行脚本。另一种响应方式是简单地提供文件。

对于CGI，Apache准备一个环境并通过CGI协议调用脚本。这是标准的Unix Fork / Exec情况-CGI子进程继承了包括套接字和标准输出的OS环境。CGI子进程编写一个响应，该响应可以返回到Apache。Apache将此响应发送到浏览器。

CGI是原始且令人讨厌的。主要是因为它为每个请求派生一个子流程，并且该子流程必须退出或关闭stdout和stderr来表示响应结束。

WSGI是基于CGI设计模式的接口。它不一定是CGI，也不必为每个请求派生一个子进程。可以是CGI，但不一定如此。

WSGI以几种重要方式添加到CGI设计模式中。它为您解析HTTP请求标头，并将其添加到环境中。它提供任何面向POST的输入，作为环境中的类似文件的对象。它还为您提供了可以制定响应的功能，从而使您免于许多格式设置细节。

如果要在基本CGI配置上运行Web框架（例如web.py或cherrypy），我需要知道/安装/做什么？

回想一下，分叉子过程很昂贵。有两种方法可以解决此问题。

  1. 在Apache中嵌入mod_wsgi或mod_python嵌入Python；没有分叉的过程。Apache直接运行Django应用程序。

  2. 守护程序， mod_wsgi或mod_fastcgi允许Apache使用WSGI协议与单独的守护程序（或“长时间运行的进程”）进行交互。您启动长期运行的Django进程，然后配置Apache的mod_fastcgi与该进程进行通信。

请注意，它mod_wsgi可以在两种模式下工作：嵌入式或守护程序。

当您阅读mod_fastcgi时，您会发现Django使用flup从mod_fastcgi提供的信息创建与WSGI兼容的接口。管道的工作原理是这样的。

Apache -> mod_fastcgi -> FLUP (via FastCGI protocol) -> Django (via WSGI protocol)

Django为各种接口提供了多个“ django.core.handlers”。

对于mod_fastcgi，Django提供了一个manage.py runfcgi集成FLUP和处理程序的。

对于mod_wsgi，有一个核心处理程序。

如何安装WSGI支持？

请遵循以下说明。

https://code.google.com/archive/p/modwsgi/wikis/IntegrationWithDjango.wiki

对于背景，请参阅此

http://docs.djangoproject.com/en/dev/howto/deployment/#howto-deployment-index

点击查看英文原文

How WSGI, CGI, and the frameworks are all connected?

Apache listens on port 80. It gets an HTTP request. It parses the request to find a way to respond. Apache has a LOT of choices for responding. One way to respond is to use CGI to run a script. Another way to respond is to simply serve a file.

In the case of CGI, Apache prepares an environment and invokes the script through the CGI protocol. This is a standard Unix Fork/Exec situation — the CGI subprocess inherits an OS environment including the socket and stdout. The CGI subprocess writes a response, which goes back to Apache; Apache sends this response to the browser.

CGI is primitive and annoying. Mostly because it forks a subprocess for every request, and subprocess must exit or close stdout and stderr to signify end of response.

WSGI is an interface that is based on the CGI design pattern. It is not necessarily CGI — it does not have to fork a subprocess for each request. It can be CGI, but it doesn’t have to be.

WSGI adds to the CGI design pattern in several important ways. It parses the HTTP Request Headers for you and adds these to the environment. It supplies any POST-oriented input as a file-like object in the environment. It also provides you a function that will formulate the response, saving you from a lot of formatting details.

What do I need to know / install / do if I want to run a web framework (say web.py or cherrypy) on my basic CGI configuration?

Recall that forking a subprocess is expensive. There are two ways to work around this.

  1. Embedded mod_wsgi or mod_python embeds Python inside Apache; no process is forked. Apache runs the Django application directly.

  2. Daemon mod_wsgi or mod_fastcgi allows Apache to interact with a separate daemon (or “long-running process”), using the WSGI protocol. You start your long-running Django process, then you configure Apache’s mod_fastcgi to communicate with this process.

Note that mod_wsgi can work in either mode: embedded or daemon.

When you read up on mod_fastcgi, you’ll see that Django uses flup to create a WSGI-compatible interface from the information provided by mod_fastcgi. The pipeline works like this.

Apache -> mod_fastcgi -> FLUP (via FastCGI protocol) -> Django (via WSGI protocol)

Django has several “django.core.handlers” for the various interfaces.

For mod_fastcgi, Django provides a manage.py runfcgi that integrates FLUP and the handler.

For mod_wsgi, there’s a core handler for this.

How to install WSGI support?

Follow these instructions.

https://code.google.com/archive/p/modwsgi/wikis/IntegrationWithDjango.wiki

For background see this

http://docs.djangoproject.com/en/dev/howto/deployment/#howto-deployment-index

回答 1

我认为Florian的答案回答了您有关“ WSGI是什么”的部分问题，特别是如果您阅读了PEP。

至于您即将提出的问题：

WSGI，CGI，FastCGI等都是Web服务器运行代码并传递产生的动态内容的协议。与此相比，静态Web服务基本上是将纯HTML文件原样发送到客户端的静态Web服务。

CGI，FastCGI和SCGI与语言无关。您可以用Perl，Python，C，bash等编写CGI脚本。CGI 根据URL 定义将调用哪个可执行文件，以及如何调用它：参数和环境。它还定义了可执行文件完成后应如何将返回值传递回Web服务器。这些变化基本上是优化的，以便能够处理更多请求，减少延迟等。基本概念是相同的。

WSGI仅适用于Python。定义了标准功能签名，而不是语言无关协议：

def simple_app(environ, start_response):
    """Simplest possible application object"""
    status = '200 OK'
    response_headers = [('Content-type','text/plain')]
    start_response(status, response_headers)
    return ['Hello world!\n']

那是一个完整的（如果有限制的话）WSGI应用程序。具有WSGI支持的Web服务器（例如具有mod_wsgi的Apache）可以在请求到达时调用此功能。

之所以如此出色，是因为我们可以避免从HTTP GET / POST转换为CGI再转换为Python的繁琐步骤，并在退出过程中再次返回。这是一种更加直接，干净和有效的链接。

如果需要对请求进行的所有操作都是函数调用，那么使长时间运行的框架在Web服务器后运行也变得更加容易。使用普通的CGI，您必须为每个单独的请求启动整个框架。

要获得WSGI支持，您需要安装WSGI模块（如mod_wsgi），或使用带有WSGI嵌入的Web服务器（如CherryPy）。如果两者都不可行，则可以使用PEP中提供的CGI-WSGI桥。

点击查看英文原文

I think Florian’s answer answers the part of your question about “what is WSGI”, especially if you read the PEP.

As for the questions you pose towards the end:

WSGI, CGI, FastCGI etc. are all protocols for a web server to run code, and deliver the dynamic content that is produced. Compare this to static web serving, where a plain HTML file is basically delivered as is to the client.

CGI, FastCGI and SCGI are language agnostic. You can write CGI scripts in Perl, Python, C, bash, whatever. CGI defines which executable will be called, based on the URL, and how it will be called: the arguments and environment. It also defines how the return value should be passed back to the web server once your executable is finished. The variations are basically optimisations to be able to handle more requests, reduce latency and so on; the basic concept is the same.

WSGI is Python only. Rather than a language agnostic protocol, a standard function signature is defined:

def simple_app(environ, start_response):
    """Simplest possible application object"""
    status = '200 OK'
    response_headers = [('Content-type','text/plain')]
    start_response(status, response_headers)
    return ['Hello world!\n']

That is a complete (if limited) WSGI application. A web server with WSGI support (such as Apache with mod_wsgi) can invoke this function whenever a request arrives.

The reason this is so great is that we can avoid the messy step of converting from a HTTP GET/POST to CGI to Python, and back again on the way out. It’s a much more direct, clean and efficient linkage.

It also makes it much easier to have long-running frameworks running behind web servers, if all that needs to be done for a request is a function call. With plain CGI, you’d have to start your whole framework up for each individual request.

To have WSGI support, you’ll need to have installed a WSGI module (like mod_wsgi), or use a web server with WSGI baked in (like CherryPy). If neither of those are possible, you could use the CGI-WSGI bridge given in the PEP.

回答 2

如Pep333所示，您可以在CGI上运行WSGI。但是，每次有一个请求时，都会启动一个新的Python解释器，并且需要构建整个上下文（数据库连接等），这都需要时间。

如果要运行WSGI，最好的方法是主机安装mod_wsgi并进行适当的配置以将控制权交给您的应用程序。

对于任何会说FCGI，SCGI或AJP的Web服务器，Flup是与WSGI一起运行的另一种方式。根据我的经验，只有FCGI确实有效，并且可以通过mod_fastcgi在Apache中使用它，或者可以通过mod_proxy_fcgi运行单独的Python守护程序。

WSGI是与CGI非常相似的协议，它定义了一组Web服务器和Python代码如何交互的规则，其定义为Pep333。这使得许多不同的Web服务器可以使用同一应用程序协议来使用许多不同的框架和应用程序。这是非常有益的，并使其非常有用。

点击查看英文原文

You can run WSGI over CGI as Pep333 demonstrates as an example. However every time there is a request a new Python interpreter is started and the whole context (database connections, etc.) needs to be build which all take time.

The best if you want to run WSGI would be if your host would install mod_wsgi and made an appropriate configuration to defer control to an application of yours.

Flup is another way to run with WSGI for any webserver that can speak FCGI, SCGI or AJP. From my experience only FCGI really works, and it can be used in Apache either via mod_fastcgi or if you can run a separate Python daemon with mod_proxy_fcgi.

WSGI is a protocol much like CGI, which defines a set of rules how webserver and Python code can interact, it is defined as Pep333. It makes it possible that many different webservers can use many different frameworks and applications using the same application protocol. This is very beneficial and makes it so useful.

回答 3

如果您不清楚这个领域中的所有术语，并且让我们直面它，这是一个令人困惑的首字母缩写词，那么还有一个很好的背景阅读器，形式为官方python HOWTO，其中讨论了CGI，FastCGI，WSGI等。上：http : //docs.python.org/howto/webservers.html

点击查看英文原文

If you are unclear on all the terms in this space, and lets face it, its a confusing acronym-laden one, there’s also a good background reader in the form of an official python HOWTO which discusses CGI vs. FastCGI vs. WSGI and so on: http://docs.python.org/howto/webservers.html

回答 4

这是用于Python的简单抽象层，类似于Servlet规范用于Java。尽管CGI确实是低级的，只是将内容转储到流程环境和标准输入/输出中，但是以上两个规范将http请求和响应建模为该语言的构造。但是，我的印象是，在Python中，人们还不太习惯实际的实现，因此您混合使用了参考实现和其他提供WSGI支持（例如Paste）的实用程序类型的库。当然，我可能是错的，我是Python的新手。“网络脚本”社区正从不同的方向提出问题（共享托管，CGI旧版，

点击查看英文原文

It’s a simple abstraction layer for Python, akin to what the Servlet spec is for Java. Whereas CGI is really low level and just dumps stuff into the process environment and standard in/out, the above two specs model the http request and response as constructs in the language. My impression however is that in Python folks have not quite settled on de-facto implementations so you have a mix of reference implementations, and other utility-type libraries that provide other things along with WSGI support (e.g. Paste). Of course I could be wrong, I’m a newcomer to Python. The “web scripting” community is coming at the problem from a different direction (shared hosting, CGI legacy, privilege separation concerns) than Java folks had the luxury of starting with (running a single enterprise container in a dedicated environment against statically compiled and deployed code).