CODEWITHSUNDEEP
xmlclojurezipper
Jacob Rahme
Jacob Rahme

Reputation: 1

Using xml-> in a let

I have some code, that parses out soap data with the use of zippers. When I format it like so it works as expected for me 

(defn parse-data
 [raw-data]
 (let [soap-data (:body raw-data)
        soap-envelope (zip/xml-zip
                    (xml/parse
                      (java.io.ByteArrayInputStream. (.getBytes (str soap-data) "UTF-8"))))]
      (pprint (xml-z/xml-> soap-envelope :soap:Envelope :soap:Body :Tag1 :Tag2))))

It prints out the expected result. But when I move the XML parsing to the let statement it fails to compile, with the following error (I've triple checked my brackets match up)

RuntimeException EOF while reading, starting at line 3  clojure.lang.Util.runtimeException (Util.java:221)
jcode.oc-drift.aquisition=>       (pprint result-data)))

CompilerException java.lang.RuntimeException: Unable to resolve symbol: result-data in this context, compiling:(/tmp/form-init6714472131112461091.clj:1:1) 
RuntimeException Unmatched delimiter: )  clojure.lang.Util.runtimeException (Util.java:221)

RuntimeException Unmatched delimiter: )  clojure.lang.Util.runtimeException (Util.java:221)
jcode.oc-drift.aquisition=>

The code was changed to put the xml-z/xml-> call into the let statement, as follows 

(defn parse-data
 [raw-data]
 (let [soap-data (:body raw-data)
        soap-envelope (zip/xml-zip
                    (xml/parse
                      (java.io.ByteArrayInputStream. (.getBytes (str soap-data) "UTF-8"))))
        result-data (xml-z/xml-> soap-envelope :soap:Envelope :soap:Body :GetNextTripsForStopResponse :GetNextTripsForStopResult)]
      (pprint result-data)))

Is this a bug with the let form, or am I missing something about the behaviour of xml-> functionality?

The full code file with the non-working function call:

src/hello/core.clj:

(ns hello.core
 (:require [clj-http.client :as http-client]
            [clojure.zip :as zip]
            [clojure.xml :as xml]
            [clojure.data.xml :as xml-data]
            [clojure.data.zip.xml :as xml-z]))

(use 'clojure.pprint)

(def app-id "redacted")
(def api-key "redacted")
(def post-data {:apiKey api-key :appID app-id})

(defn get-data
 [post-data function]
 "function is a string with the api function to be called"
  (let [url (str "redacted" function)]
   (http-client/post url {:form-params post-data})))

(defn parse-data
 [raw-data]
 (let [soap-data (:body raw-data)
        soap-envelope (zip/xml-zip
                    (xml/parse
                      (java.io.ByteArrayInputStream. (.getBytes (str soap-data) "UTF-8"))))
        result-data (xml-z/xml-> soap-envelope :soap:Envelope :soap:Body :GetNextTripsForStopResponse :GetNextTripsForStopResult)]
      (pprint result-data)))

project.clj:

(defproject hello "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "Eclipse Public License"
            :url "http://www.eclipse.org/legal/epl-v10.html"}
  :main hello.core
  :dependencies [[org.clojure/clojure "1.7.0"]                 
                 [org.clojure/data.xml "0.0.8"]
                 [org.clojure/data.zip "0.1.2"]
                 [clj-http "2.2.0"]])

Upvotes: 0

Views: 148

Answers (2)

Alan Thompson
Alan Thompson

Reputation: 29958

The code you pasted is working for me. I think the problem must be related to the repl you are using, the editor/repl combo, or something else. Create a new project and paste in the following:

> lein new app hello

Then edit the 2 files:

project.clj

(defproject hello 
  "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "Eclipse Public License"
            :url "http://www.eclipse.org/legal/epl-v10.html"}
  :main hello.core
  :dependencies [[org.clojure/clojure "1.7.0"]                 
                 [org.clojure/data.xml "0.0.8"]
                 [org.clojure/data.zip "0.1.2"]
                 [clj-http "2.2.0"]] )

src/hello/core.clj

(ns hello.core
  (:require [clj-http.client :as http-client]
            [clojure.zip :as zip]
            [clojure.xml :as xml]
            [clojure.data.xml :as xml-data]
            [clojure.data.zip.xml :as xml-z]))

(use 'clojure.pprint)

(def app-id "redacted")
(def api-key "redacted")
(def post-data {:apiKey api-key :appID app-id})

(defn get-data
 [post-data function]
 "function is a string with the api function to be called"
  (let [url (str "redacted" function)]
   (http-client/post url {:form-params post-data})))

(defn parse-data
 [raw-data]
 (let [soap-data (:body raw-data)
        soap-envelope (zip/xml-zip
                    (xml/parse
                      (java.io.ByteArrayInputStream. (.getBytes (str soap-data) "UTF-8"))))
        result-data (xml-z/xml-> soap-envelope :soap:Envelope :soap:Body :GetNextTripsForStopResponse :GetNextTripsForStopResult)]
      (pprint result-data)))

(defn -main
  "I don't do a whole lot ... yet."
  [& args]
  (println "Hello, World!"))

Then run it from the command line

> lein run    
Hello, World!

No compiler errors (of course, without test data, we didn't actually call any of your functions, either).

It looks like the problem is somewhere in your environment. If you clean everything out and start fresh in a new project you should see the same results.

Upvotes: 1

Arthur Ulfeldt
Arthur Ulfeldt

Reputation: 91534

the code you pasted is correct, and does not have the problem pasted in that stacktrace.

specifically the error shows Unable to resolve symbol: result-data and from the line above that it looks like it closed the expression before it got to the line with 

 (pprint result-data)))

This sounds like a case where there is a syntax error higher in the buffer. For instance if higher up in the program there was an unbalanced [ or ( .

because the extra opening paren would match this one and end the expression early. The two errors after that add evidence to this leading me to think that it's interpreting the `(pprint result-data)))`` as the start of a new expression with two extra parens on the end.

try:

  • clear the buffer (in cider press , then type clear) and try it again.
  • try restarting nrepl (in cider press , then typre restart) and try again.

running your code works correct both when run in a repl and when evaluated from a file (these are exactly the same opperation)

hello.core> (defn parse-data
              [raw-data]
              (let [soap-data (:body raw-data)
                    soap-envelope (zip/xml-zip
                                   (xml/parse
                                    (java.io.ByteArrayInputStream. (.getBytes (str soap-data) "UTF-8"))))]
                (pprint (xml-z/xml-> soap-envelope :soap:Envelope :soap:Body :Tag1 :Tag2))))
#'hello.core/parse-data
hello.core> (defn parse-data
              [raw-data]
              (let [soap-data (:body raw-data)
                    soap-envelope (zip/xml-zip
                                   (xml/parse
                                    (java.io.ByteArrayInputStream. (.getBytes (str soap-data) "UTF-8"))))
                    result-data (xml-z/xml-> soap-envelope :soap:Envelope :soap:Body :GetNextTripsForStopResponse :GetNextTripsForStopResult)]
                (pprint result-data)))
#'hello.core/parse-data

so this really looks like an environment problem. Here are some more things to check:

  • the repl is in the correct namespace
  • no extra characters are being added or changed in the cut-and-paste process
  • paredit-mode is not auto-closing expressions as they are pasted in.
  • no "smart quotes" have been inserted by clipboard managers.
  • the code works if you run lean repl and paste the lines in
  • lein check loads the file without complaints (other than reflection warnings)

Upvotes: 1

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