Question

我一直在玩弄龙卷风, 我写了一些代码似乎不怎么好。

我在写一个程序来存储食谱,作为一个例子。这些是我的处理者:

handlers = [
    (r"/recipes/", RecipeHandler),
    (r"/recipes", RecipeSearchHandler), #so query params can be used to search
]

这让我写到:

class RecipeHandler(RequestHandler):      
    def get(self):
        self.render( recipes/index.html )

class RecipeSearchHandler(RequestHandler):    
    def get(self):
        try:
            name = self.get_argument( name , True)
            self.write(name)
        # will do some searching
        except AssertionError:
            self.write("no params")
            # will probably redirect to /recipes/

是否有更好的方法可以不尝试/ 例外地处理这些 URL? 我喜欢/ recipes 和 / recipes/ 来显示同样的东西, 而 / recipes? name = something 会做搜索, 最好换个处理器。

Answer 1

在龙卷风源中有一个演示,请访问 https://github.com/facebook/transado/blob/master/demos/blog/blog.py#L87。

# url handler
handlers = [(r"/entry/([^/]+)", EntryHandler),]

class EntryHandler(BaseHandler):
    def get(self, slug):
        entry = self.db.get("SELECT * FROM entries WHERE slug = %s", slug)
        if not entry: raise tornado.web.HTTPError(404)
        self.render("entry.html", entry=entry)

任何符合正则表达式的“ 文本” 将被传递到条目Handlers 获取方法作为弹簧参数。如果 URL 与任何处理器不匹配, 用户将收到404 个错误。

如果您想要提供另一个后退, 您可以让参数可选

(r"/entry/([^/]*)", EntryHandler),

class EntryHandler(BaseHandler):
    def get(self, slug=None):
        pass

<强> 更新:

+1 for the link. However does this URL pattern extend to include more parameters if I wanted to search like this... /recipes?ingredient=chicken&style=indian – colinjameswebb

是的,它确实有。

handlers = [
     (r /(d{4})/(d{2})/(d{2})/([a-zA-Z-0-9.:,_]+)/? , DetailHandler)
]

class DetailHandler(BaseHandler):
    def get(self, year, month, day, slug):
        pass

Answer 2

get_argument 允许您提供默认值 :

details=self.get_argument("details", None, True)

如果不提供理由,就不会出现例外,如果没有提供理由

Answer 3

Tornado also has a get_arguments function. It returns a list of arguments with the given name. If not present, it returns an empty list ( [] ). I found it cleaner this way to sanitize your web service inputs instead of try..catch blocks.

Sample:
Assume I have a following URL handler:

(r"/recipe",GetRecipe)

And the request handler:

class GetRecipe(RequestHandler):
    def get(self):
        recipe_id = self.get_arguments("rid")
        if recipe_id == []:
            # Handle me
            self.set_status(400)
            return self.finish("Invalid recipe id")
        self.write({"recipe_id":self.get_argument("rid")})

recipe_id list will also hold the value but I found self.get_argument usage convenient this way.

Now for the results:

curl "http://localhost:8890/recipe" -v

*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 8890 (#0)
> GET /recipe HTTP/1.1
> User-Agent: curl/7.35.0
> Host: localhost:8890
> Accept: */*
> 
< HTTP/1.1 400 Bad Request
< Content-Length: 17
< Content-Type: text/html; charset=UTF-8
* Server TornadoServer/1.1.1 is not blacklisted
< Server: TornadoServer/1.1.1
< 
* Connection #0 to host localhost left intact
Invalid recipe id

curl "http://localhost:8890/recipe?rid=230" -v
*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 8890 (#0)
> GET /recipe?rid=230 HTTP/1.1
> User-Agent: curl/7.35.0
> Host: localhost:8890
> Accept: */*
> 
< HTTP/1.1 200 OK
< Content-Length: 20
< Etag: "d69ecb9086a20160178ade6b13eb0b3959aa13c6"
< Content-Type: text/javascript; charset=UTF-8
* Server TornadoServer/1.1.1 is not blacklisted
< Server: TornadoServer/1.1.1
< 
* Connection #0 to host localhost left intact
{"recipe_id": "230"}

Answer 4

如果您想要使用更动态的过滤方法( 而不是硬编码的 URL), 您可以在请求处理器中使用 < code> self. request. arguments 来获取所有已通过的 URL 参数/ 参数。

class ApiHandler(RequestHandler):
    def get(self, path):
        filters = self.request.arguments
        for k,v in filters.items():
            # Do filtering etc...

见http://www.tradesradoweb.org/en/stable/httputil.html#traterado.httputil.HTTPServer request.arguments' rel=“noreferrer'>http://www.tradesadoweb.org/en/stable/httpttil.html#traterado.attil.httputil.HTTPServer request.arguments

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