From c65fb8680e78f9d72c2fa8fcd170543c816aafe6 Mon Sep 17 00:00:00 2001 From: geekpi Date: Tue, 26 May 2020 08:41:57 +0800 Subject: [PATCH] translated --- ...nguages you should (probably) never use.md | 180 ------------------ ...nguages you should (probably) never use.md | 179 +++++++++++++++++ 2 files changed, 179 insertions(+), 180 deletions(-) delete mode 100644 sources/tech/20200401 3 Python templating languages you should (probably) never use.md create mode 100644 translated/tech/20200401 3 Python templating languages you should (probably) never use.md diff --git a/sources/tech/20200401 3 Python templating languages you should (probably) never use.md b/sources/tech/20200401 3 Python templating languages you should (probably) never use.md deleted file mode 100644 index 7d73216ea5..0000000000 --- a/sources/tech/20200401 3 Python templating languages you should (probably) never use.md +++ /dev/null @@ -1,180 +0,0 @@ -[#]: collector: (lujun9972) -[#]: translator: (geekpi) -[#]: reviewer: ( ) -[#]: publisher: ( ) -[#]: url: ( ) -[#]: subject: (3 Python templating languages you should (probably) never use) -[#]: via: (https://opensource.com/article/20/4/python-templating-languages) -[#]: author: (Moshe Zadka https://opensource.com/users/moshez) - -3 Python templating languages you should (probably) never use -====== -Python has accumulated a lot of templating languages, including these -three that are perfect for April Fools' Day. -![Hands on a keyboard with a Python book ][1] - -When reaching for a templating language for writing a [Python][2] web application, there are an abundance of robust solutions.  - -There are [Jinja2][3], [Genshi, and Mako][4]. There are even solutions like [Chameleon][5], which are a bit older, but still recommended by the [Pyramid][6] framework. - -Python has been around for a long time. In that time, deep in the corners of its system, it has accumulated some almost forgotten templating languages that are well worth poking at. - -Like cute koalas on top of a eucalyptus tree, happy in their ecological niche, and sometimes as dangerous to work with, these are the templating languages few have heard of—and even fewer should use. - -### 3\. string.Template - -Have you ever wondered, "How can I get a templating language with no features, but also without needing to **pip install** anything?" The Python standard library has you covered. While it does no looping or conditionals, the **string.Template** class is a minimal templating language. - -Using it is simplicity itself. - - -``` ->>> import string ->>> greeting = string.Template("Hello, $name, good $time!") ->>> greeting.substitute(name="OpenSource.com", time="afternoon") -'Hello, OpenSource.com, good afternoon!' -``` - -### 2\. twisted.web.template - -What gift do you give the library that has everything? - -Not a templating language, certainly, because it already has one. Nestled in **twisted.web.template** are two templating languages. One is XML-based and has a [great tutorial][7]. - -But there is another one, one that is based on using Python as a domain-specific language to produce HTML documents. - -It is based on two primitives: **twisted.web.template.tags**, which contains tag objects, and **twisted.web.template.flattenString**, which will render them. Because it is part of Twisted, it has built-in support for rendering async results efficiently. - -This example will render a silly little page: - - -``` -async def render(reactor): -    my_title = "A Fun page" -    things = ["one", "two", "red", "blue"] -    template = tags.html( -            tags.head( -                tags.title(my_title), -            ), -            tags.body( -                tags.h1(my_title), -                tags.ul( -                    [tags.li(thing) for thing in things], -                ), -                tags.p( -                    task.deferLater(reactor, 3, lambda: "Hello "), -                    task.deferLater(reactor, 3, lambda: "world!"), -                ) -            ) -    ) -    res = await flattenString(None, template) -    res = res.decode('utf-8') -    with open("hello.html", 'w') as fpout: -        fpout.write(res) -``` - -The template is regular Python code that uses the **tags.<TAGNAME>** to indicate the hierarchy. It natively supports strings as renderables, so any string is fine. - -To render it, the only things you need to do are to add a preamble: - - -``` -from twisted.internet import task, defer -from twisted.web.template import tags, flattenString - -def main(reactor): -    return defer.ensureDeferred(render(reactor)) -``` - -and an epilogue to run the whole thing: - - -``` -`task.react(main)` -``` - -In just _three_ seconds (and not _six_), it will render a nice HTML page. In real-life, those **deferLater**s can be, for example, calls to an HTTP API: they will be sent and processed in parallel, without having to put in any effort. I recommend you instead read about a [far better use for Twisted][8]. But still, this works. - -### 1\. Quixote - -You will say, "But Python is not _optimized_ for being an HTML-spouting domain-specific language." What if, instead of settling for Python-as-is, there was a language that [transpiles][9] to Python, but is better at defining templates? A "Python template language" (PTL), if you will. - -Writing your own language is sometimes said to be a dreamer's project for someone who tilts at windmills. Irony was not lost on the creators of Quixote (available on [PyPI][10]) when they decided to do exactly that. - -The following will render an equivalent template to the one done with Twisted above. _Warning: the following is not valid Python_: - - -``` -import time - -def render [html] (): -    my_title = "A Fun page" -    things = ["one", "two", "red", "blue"] -    "<html><head><title>" -    my_title -    "</head></title><body><h1>" -    my_title -    "</h1>" -    "<ul>" -    for thing in things: -        "<li>" -        thing -        "</li>" -    "<p>" -    time.sleep(3) -    (lambda: "Hello ")() -    time.sleep(3) -    (lambda: "world!")() -    "</p>" -    "</body></html>" - -def write(): -    result = render() -    with open("hello.html", 'w') as fpout: -        fpout.write(str(result)) -``` - -However, if you put it in a file called **template.ptl**, you can make it importable to Quixote and write out the rendered version of the template: - - -``` ->>> from quixote import enable_ptl ->>> enable_ptl() ->>> import template ->>> template.write() -``` - -Quixote installs an import hook that will cause PTL files to transpile into Python. Note that this render takes _six_ seconds, not _three_; you no longer gain free asynchronicity. - -### So many templates in Python - -Python has a long and winding history of libraries, some of which can achieve the same outcomes in more or less similar ways (for example, Python [package management][11]). - -On this April Fools' Day, I hope you enjoyed exploring three ways you _can_ create templates in Python. Instead, I recommend starting with [one of these libraries][4] for ways you _should_ template. - -Do you have another esoteric way to template? Share it in the comments below! - --------------------------------------------------------------------------------- - -via: https://opensource.com/article/20/4/python-templating-languages - -作者：[Moshe Zadka][a] -选题：[lujun9972][b] -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]: https://opensource.com/users/moshez -[b]: https://github.com/lujun9972 -[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/python-programming-code-keyboard.png?itok=fxiSpmnd (Hands on a keyboard with a Python book ) -[2]: https://opensource.com/resources/python -[3]: https://opensource.com/article/20/2/jinja2-cheat-sheet -[4]: https://opensource.com/resources/python/template-libraries -[5]: https://chameleon.readthedocs.io/en/latest/ -[6]: https://opensource.com/article/18/5/pyramid-framework -[7]: https://twistedmatrix.com/documents/13.1.0/web/howto/twisted-templates.html -[8]: https://opensource.com/article/20/3/treq-python -[9]: https://en.wikipedia.org/wiki/Source-to-source_compiler -[10]: https://pypi.org/project/Quixote/ -[11]: https://opensource.com/article/19/4/managing-python-packages diff --git a/translated/tech/20200401 3 Python templating languages you should (probably) never use.md b/translated/tech/20200401 3 Python templating languages you should (probably) never use.md new file mode 100644 index 0000000000..b28d03f589 --- /dev/null +++ b/translated/tech/20200401 3 Python templating languages you should (probably) never use.md @@ -0,0 +1,179 @@ +[#]: collector: (lujun9972) +[#]: translator: (geekpi) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: url: ( ) +[#]: subject: (3 Python templating languages you should (probably) never use) +[#]: via: (https://opensource.com/article/20/4/python-templating-languages) +[#]: author: (Moshe Zadka https://opensource.com/users/moshez) + +你应该（或许）没使用过的 3 种 Python 模板语言 +====== +Python 积累了许多模板语言，包括这 3 个适合在愚人节介绍的模板语言 +![Hands on a keyboard with a Python book ][1] + +当使用一种模板语言来编写 [Python][2] Web 应用时，它有很多健壮的解决方案。 + +有 [Jinja2][3]、[Genshi 和 Mako][4]。甚至还有 [Chameleon][5] 之类的解决方案，虽然有些陈旧，但仍被 [Pyramid][6] 框架推荐。 + +Python 已经存在了很长时间。此时，在系统的深处，它积累了一些几乎被遗忘的模板语言，它们都是值得一试的。 + +就像桉树顶上的可爱考拉一样，在它们的生态位中不错，有时用它们工作会危险，这些都是很少有人听说过的模板语言，使用过的应该更少。 + +### 3\. string.Template + +你是否曾经想过：“如何获得一种没有任何特性但同时也不需要 **pip install** 的模板语言？” Python 标准库已经涵盖。虽然没有循环和条件，但 **string.Template** 类是一种最小的模板语言。 + +使用它很简单。 + + +``` +>>> import string +>>> greeting = string.Template("Hello, $name, good $time!") +>>> greeting.substitute(name="OpenSource.com", time="afternoon") +'Hello, OpenSource.com, good afternoon!' +``` + +### 2\. twisted.web.template + +你会给一个有所有东西的库什么礼物？ + +当然，它不是一种模板语言，因为已经有一种。 嵌套在 twisted.web.template 中的是两种模板语言。 一种是基于 XML 的，并有一个[很棒的文档][7]。 + +但是还有另一种，一种基于使用 Python 作为领域特定语言来生成 HTML 文档。 + +它基于两个原语：包含标签对象的 **twisted.web.template.tags** 和渲染它们的 **twisted.web.template.flattenString**。由于它是 Twisted 的一部分，因此它内置支持高效异步渲染。 + +此例将渲染一个小页面： + + +``` +async def render(reactor): +    my_title = "A Fun page" +    things = ["one", "two", "red", "blue"] +    template = tags.html( +            tags.head( +                tags.title(my_title), +            ), +            tags.body( +                tags.h1(my_title), +                tags.ul( +                    [tags.li(thing) for thing in things], +                ), +                tags.p( +                    task.deferLater(reactor, 3, lambda: "Hello "), +                    task.deferLater(reactor, 3, lambda: "world!"), +                ) +            ) +    ) +    res = await flattenString(None, template) +    res = res.decode('utf-8') +    with open("hello.html", 'w') as fpout: +        fpout.write(res) +``` + +该模板是使用 **tags.<TAGNAME>** 来指示层次结构的常规 Python 代码。原生支持渲染字符串，因此任何字符串都正常。 + +要渲染它，你需要做的是添加调用： + + +``` +from twisted.internet import task, defer +from twisted.web.template import tags, flattenString + +def main(reactor): +    return defer.ensureDeferred(render(reactor)) +``` + +最后写上： + + +``` +`task.react(main)` +``` + +只需 _3_ 秒（而不是 _6_ 秒），它将渲染一个不错的 HTML 页面。在实际中，这些 **deferLater** 可以是对 HTTP API 的调用：它们将并行发送和处理，而无需花费精力。我建议你阅读关于[更好地使用 Twisted][8]。但是，这仍可以工作。 + +### 1\. Quixote + +你会说：“但是 Python 并不是针对 HTML 输入而优化的领域特定语言。” 如果有一种语言可以[转化][9]到 Python，但是更适合定义模板，而不是像 Python 那样按原样解决呢？ 如果可以的话，请使用“Python 模板语言”（PTL）。 + +对于攻击假想敌的人来说，写自己的语言有时被认为是梦想家的项目。当 Quixote （可用于 [PyPI][10]）的创造者决定这样做时，并没有受此影响。 + +以下将渲染与上面 Twisted 相同的模板。 _警告：以下是无效的 Python_： + + +``` +import time + +def render [html] (): +    my_title = "A Fun page" +    things = ["one", "two", "red", "blue"] +    "<html><head><title>" +    my_title +    "</head></title><body><h1>" +    my_title +    "</h1>" +    "<ul>" +    for thing in things: +        "<li>" +        thing +        "</li>" +    "<p>" +    time.sleep(3) +    (lambda: "Hello ")() +    time.sleep(3) +    (lambda: "world!")() +    "</p>" +    "</body></html>" + +def write(): +    result = render() +    with open("hello.html", 'w') as fpout: +        fpout.write(str(result)) +``` + +但是，如果将它放到 **template.ptl** 文件中，那么可以将其导入到 Quixote 并写出可以渲染模板的版本： + + +``` +>>> from quixote import enable_ptl +>>> enable_ptl() +>>> import template +>>> template.write() +``` + +Quixote 安装一个导入钩子，它会将 PTL 文件转换为 Python。请注意，此渲染需要 _6_ 秒，而不是 _3_ 秒。你不再能自由异步。 + +### Python 中的模板太多 + +Python 的库历史悠久且曲折，其中一些库可以或多或少以类似的方式实现相同的结果（例如，Python [包管理][11]）。 + +在这个愚人节，我希望你喜欢探索这三种_可以_用 Python 创建模板的方式。另外，我建议从[这三个库之一][4]开始了解。 + +你是否有另一种深奥的模板方法？请在下面的评论中分享！ + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/20/4/python-templating-languages + +作者：[Moshe Zadka][a] +选题：[lujun9972][b] +译者：[geekpi](https://github.com/geekpi) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/moshez +[b]: https://github.com/lujun9972 +[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/python-programming-code-keyboard.png?itok=fxiSpmnd (Hands on a keyboard with a Python book ) +[2]: https://opensource.com/resources/python +[3]: https://opensource.com/article/20/2/jinja2-cheat-sheet +[4]: https://opensource.com/resources/python/template-libraries +[5]: https://chameleon.readthedocs.io/en/latest/ +[6]: https://opensource.com/article/18/5/pyramid-framework +[7]: https://twistedmatrix.com/documents/13.1.0/web/howto/twisted-templates.html +[8]: https://opensource.com/article/20/3/treq-python +[9]: https://en.wikipedia.org/wiki/Source-to-source_compiler +[10]: https://pypi.org/project/Quixote/ +[11]: https://opensource.com/article/19/4/managing-python-packages