在沙发床重写规则中追加到变量 [英] append to variable in couchdb rewrite rule

问题描述

我正在尝试创建一个重写规则，以读取一个以字符串开头的键的视图。

I am trying to create a rewrite rule, to read a view with keys that start with a string.

我可以在不进行重写的情况下做到这一点，但很费劲

I can do this without the rewrite, but am struggling to do it with the rewrite.

curl -g -H "Accept: application/json" \
    'http://127.0.0.3:80/bookmarks/_design/design/_view/webmarks-by-url?include_docs=true&reduce=false&startkey=["www.sciencemuseum.org.uk"]&endkey=["www.sciencemuseum.org.uk/\ufff0"]' | json_pp

然后我尝试使用rewrites.json

Then I try to do it with a rewrites.json

{
    "from": "bookmarks_by_url/:~name:",
    "to": "_view/webmarks-by-url",
    "query": {
        "reduce": "false",
        "include_docs": "true",
        "descending" : "false",
        "startkey": [":~name:"],
        "endkey": [":~name:\ufff0"]
    }       
},

我想要的东西，但这显然行不通。有没有办法说这是变量的结尾？还是写规则的另一种方式？

What I want, but this is obviously not going to work. Is there a way to say this is the end of a variable? Or another way to write the rule?

{
    "from": "bookmarks_by_url/:~name:",
    "to": "_view/webmarks-by-url",
    "query": {
        "reduce": "false",
        "include_docs": "true",
        "descending" : "false",
        "startkey": [":~name:"],
        "endkey": [":~name:" + "\ufff0"]
    }       
},

---

有关重写规则的文档非常糟糕，如果您知道更好的规则，请链接。

---

The documentation for rewrite rules are terrible, If you know of better ones then please link.

推荐答案

如果您使用的是Couch 2.1+，您可以使用 JS重写使用普通JS函数进行请求路由。

If you are using Couch 2.1+, you may employ JS rewrites to use plain JS function for request routing.

具有 .rewrites 部分，其中包含路由器函数的字符串表示形式，您可以处理非常复杂的路由。此外，您甚至可以直接通过重写功能提供响应。

Having .rewrites section, containing a string representation of a router function, you can handle very complex routing. Moreover, you can even serve a response directly from rewrite function.

但是，使用JS重写，您还会受到所有JS查询服务器的处罚。它们是：

However, using JS rewrites you also have all JS query server penalties. They are:

• 为每个请求延迟添加几毫秒。


• 您的重写fn是单线程瓶颈，您无法处理超出重写fn能够处理的请求。


• 由于Couch中的每个JS引擎实例都只有64Mb的RAM用于编译代码和数据，您无法处理大型POST请求。


• Couch中的所有QS功能都很难调试，重写也不例外。


• 您可以

• You add several ms to each request latency.
• Your rewrite fn is a single-threaded bottleneck, you can’t handle more requests than your rewrite fn is able to process.
• Since each JS engine instance in Couch has only 64Mb RAM for both compiled code and data, you can’t process large POST requests.
• All QS functions in Couch are hard to debug, rewrite is not an exception.
• You can’t use both old array syntax (which is waaay faster), and a function in one design doc.

因为我亲自雇用JS重写，所以既要使用旧的数组语法（速度更快），又要在一个设计文档中使用函数。在很大程度上，我可以说优点比缺点要重得多。 有一篇文章，其中包含一些与JS重写有关的性能细节。

Since I personally employ JS rewrite heavily, I can say pros are much heavier than cons. There is an article with some perf details related to JS rewrites.

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