I am getting the body and headers from the request like this:
(POST "/api/item" {body :body headers :headers} (create-item body headers))
The body is wrapped, so I get a keyword map and I can easily take values from the that:
(def app
(-> (handler/api app-routes)
(middleware/wrap-json-body {:keywords? true})
(middleware/wrap-json-response)))
As simple as:
(:item-name body)
How can I achieve the same with the headers, or just simply take a specific header value? Do I have to map the headers into a Clojure data structure first?
If I print headers I get something like this:
({host localhost:3000, user-agent Mozilla/5.0})
The headers are already in a Clojure data structure. If you want a better idea of the data types present, use prn instead of println, and you will see that it is a a hash-map with strings as keys.
(:foo x) is a shortcut for (get x :foo). For a hash-map with string keys you can get a value with eg. (get headers "host"). There is a function in clojure.walk, clojure.walk/keywordize-keys that will turn keys of a data structure into keywords, recursively through a nested structure. IMHO this is a bit silly, and one is better off using get and the string keys in most cases.
Related
The ClojureScript cljs-ajax client library converts {:b [1 2]} to b[0]=1&b[1]=2
For example:
(http/get "http://example.com" {:b [1 2]})
results in a request to:
"http://example.com?b[0]=1&b[1]=2"
How can I setup my ring middleware to handle this format on the server side? I would like to convert it back to the original structure:
{:b [1 2]}
I am using the middleware below, but it does not work properly:
(ring.middleware.keyword-params/wrap-keyword-params)
(ring.middleware.params/wrap-params :encoding encoding)
(ring.middleware.nested-params/wrap-nested-params)
There is no issue in middleware side. The issue is in cljs-ajax's ajax.core/params-to-str api. It is generating duplicate URL for different data format.
(ajax.core/params-to-str {:b [1 3]})
;; => "b[0]=1&b[1]=3"
(ajax.core/params-to-str {:b {0 1 1 3}})
;; => "b[0]=1&b[1]=3"
For array, format should be b[]=1&b[]=3.
I would suggest the middleware is working fine, but perhaps there is a misalignment between what it does and your expectations. I'm assuming that what you have above is just a list of the middleware and not how you are calling/using it. If not, your way off track.
Strictly speaking, what you are trying to pass is not a nested parameter. What you really have are parameters with names like "b[0]" and "b[1]", which each have a value. This is because you are using get rather than post and cljs-ajax needs to translate your clojure data structure to normal query parameter format. Unless there is a strong reason to do this, you will find life much easier if you use a post method rather than get and embed the data in the body as json/edn/transit whatever. It also has the added benefit that your data won't be sent 'public' as part of the URL and captured by logs all over the place.
A useful server side package to use with cljs-ajax and post commands is ring.middleware.format. This will simplify the parsing of the data in the body of your request and supports multiple different data encoding methods.
How can I list all the routes on a handler function? I'm looking for behavior similar to rails' rake routes. For example:
(defroutes foo-routes
(GET "/foo/:foo-id"
[foo-id]
"bar response")
(GET "/bar/:bar-id"
[bar-id]
"foo response"))
Is it then possible to extract a map from foo-bar-routes containing the following?
{:GET "/foo/:foo-id"
:GET "/bar/:bar-id"}
I don't think it is possible. defroutes is a macro that returns a ring handler. GET is a macro that returns a route. Route is again just a function that calls related handler only if method and path are matching. So in the end your foo-routes is just a clojure function that is composed of other functions defined by your routes and it doesn't maintain such map. If you need to get such map, maybe you can maintain it in your code yourself and generate routes out of this map.
I know this thread is quite old but I had the same question and could resolve it by myself, here's what I've got:
Assuming you defined your API this way:
(def my-api (compojure.api.api/api ...))
Then you can easily list the routes you defined that way:
(->> (.-get-routes my-api {})
(map (juxt second first)))
I am wondering what magic is occurring for this code from https://github.com/weavejester/compojure/wiki/Destructuring-Syntax
(GET "/" request
(str request))
I would expect it to look something like
(GET "/" [request]
(str request))
Specifically, how is the request bound to the second argument?
Is the request always bound to the second argument?
What differentiates request vs [request]?
I have changed my code to see what happens in each of these scenarios, just trying to understand the reason and make sure I don't make and wrong assumptions about the second arg being bound to the request.
Thanks
-jv
The request map is always bound to the second argument passed to the route macros. If you bind it as map, it will be destructored via regular Clojure Map binding destructoring. If you bind it as a vector, Compojures macro looks the symbols up as equally named keys in the :params map of the request map. The latter is Compojure specific and explained in the link you provided with the question.
The binding takes place by the GET macro transforming the forms you pass to it into sourcecode of a request handler function with the desired lookups in scope.
The first example binds request to the entire request map.
The second example binds request to the value of key :request of the map of key :params of the request map.
NOTE: I resolved my issue. However, it took a number of incremental changes. If you happen upon this page, feel free to checkout my github below to see how I made this application work.
I am using http-kit to post a request to btc-china. I want to use their trading api. I am able to do this just fine with python, but for some reason I keep getting 401s with clojure and http-kit. I've posted a snippit of code below which may show that I am not using http-kit correctly. In addition to that, here is a github for my full code if you wish to look at that: https://github.com/gilmaso/btc-trading
Here are the btc-china api docs: http://btcchina.org/api-trade-documentation-en
(def options {:timeout 2000 ; ms
:query-params (sorted-map :tonce tonce
:accesskey access-key
:requestmethod request-method
:id tonce
:method method
:params "")
:headers {"Authorization" auth-string
"Json-Rpc-Tonce" tonce}})
(client/post (str "https://" base-url) options
(fn [{:keys [status headers body error]}] ;; asynchronous handle response
(if error
(println "Failed, exception is " error)
(println "Async HTTP GET: " status))))
quoting from the example on the bttchina site:
# The order of params is critical for calculating a correct hash
clojure hash maps are unordered, and you cannot use a clojure hash map literal to provide the input if order is significant
I had very similar problem with bitstamp api. The solution was to replace :query-params with :form-params. Then the parameters are sent in the body. I noticed that in your api you are manually sending then in the body. It looks like using :form-params might help in your case as well.
I am trying to write a middleware for converting all the string object ids in the request to ObjectId objects.
I am achieving this using the following:
(defn get-object-id
[id]
(when (and (string? id) (re-matches object-id-regex id))
(ObjectId. id)))
(defn maybe-obj->object-id [obj]
(or (get-object-id obj) obj))
(defn- convert-string->object-ids [obj]
(cwalk/postwalk
(partial pcommon/maybe-obj->object-id) obj))
(defn warp-params-string->objectid
"convert strings to object ids"
[handler]
(fn [request]
(handler (update-in request [:params] convert-string->object-ids))))
This is working for all the params coming for json, request params etc. But this is not applying to the route params, e.g. :fst for url "/:fst". I looked at the GET macro and the route params are being injected somewhere inside that macro. However since GET/POST etc are executed last, my middlewares do not have access to these. Any graceful way of achieving this.
Those /:foo/:bar-style parameters get bound as a result of pattern matching on URIs, with the patterns specified in the individual routes' definitions. Outer layers don't even know what the patterns look like. So, not really possible to lift processing of these to middleware.
Instead, you could write a macro, say with-preprocessed-params, to wrap your route handlers' bodies in. If it ends up being useful in many handlers, you can additionally provide your own versions of GET & Co., delegating to Compojure's macros with the body wrapped in your param-processing macro.
That's not really a good solution if you were hoping to use the results of this preprocessing in further layers of middleware. In that case, assuming you're happy to leave matching actual URI path segments to the core handler layer, you can perform your preprocessing of other parameter types in a piece of middleware, then use your GET & Co. variants to preprocess the route parameters only.