Support listing in res fs

Author: Francesco Macagno

CHANGELOG.md

@@ -1,6 +1,8 @@
 # Changelog
 
 ## Unreleased
+### Added
+- Support for listing in resource filesystem.
 
 ## [1.2.3] - 2023-01-09
 ### Fixed

README.md

@@ -19,7 +19,7 @@ Features:
 |[hdfs](#hdfs)     |  •  |  •  |  •  |   •   |  •   |  •  |  •  |  •  |`hdfs://[host]/path/to/file.txt`        |
 |[http(s)](#https) |  •  |     |:cat:| :cat: |      |     |     |     |`http[s]://host[:port]/path/to/file.txt`|
 |[mem](#mem)       |  •  |  •  |  •  |   •   |  •   |  •  |  •  |  •  |`mem:///path/to/file.txt`               |
-|[res](#res)       |  •  |     |     |   •   |      |     |     |     |`res:///com/mypackage/file.txt`         |
+|[res](#res)       |  •  |     |     |   •   |      |     |  •  |     |`res:///com/mypackage/file.txt`         |
 |[s3](#s3)         |  •  |  •  |  •  |   •   |  •   |:dog:|  •  |  •  |`s3://bucket/key/with/slashes.txt`      |
 |[sftp](#sftp)     |  •  |:bug:|  •  |   •   |:pig: |  •  |  •  |  •  |`sftp://host[:port]/path/to/file.txt`   |
 

project.clj

@@ -40,6 +40,7 @@
                   "-target" "1.8"
                   "-Xlint:deprecation"
                   "-Xlint:unchecked"]
+  :resource-paths ["resources"]
 
   :profiles {:dev {:dependencies [[midje "1.9.2"]]
                    :plugins      [[lein-midje "3.2.1"]]}}

resources/test/test.txt

@@ -0,0 +1 @@
+gdbg

src/uio/fs/res.clj

@@ -4,8 +4,10 @@
 ;     ^^^ triple slash
 ;
 (ns uio.fs.res
-  (:require [uio.impl :refer :all])
-  (:import (clojure.java.api Clojure)))
+  (:require
+    [uio.impl :refer :all])
+  (:import (clojure.java.api Clojure)
+           (java.io File)))
 
 (defn assert-res-url [url]
   (if (host url)
@@ -20,3 +22,15 @@
 (defmethod exists? :res [url & args] (if (.getResource Clojure (path (assert-res-url url)))
                                        true
                                        false))
+
+(defmethod ls :res [url & args]
+  (->>
+    (.substring (path (normalize url)) 1)                   ; get path and remove leading slash
+    (.getResources (.getClassLoader Clojure))               ; Multiple resources can have the same name
+    (enumeration-seq)
+    (map #(File. (.getPath %)))
+    (map #(if (.isFile %)
+            %
+            (seq (.listFiles %))))
+    (flatten)                                               ; If it's a directory, flatten the list of files.
+    (map #(do {:url (str "file://" %)}))))                  ; expected format is a list of maps

test/uio/fs/test_res.clj

@@ -0,0 +1,25 @@
+(ns uio.fs.test-res
+  (:require [midje.sweet :refer :all]
+            [uio.fs.mem :refer :all]
+            [uio.impl :refer :all]))
+
+(facts "from"
+  (slurp (from "res:///test/test.txt")) => "gdbg\n")
+
+(facts "exists"
+  (exists? "res:///") => true
+  (exists? "res:///test") => true
+  (exists? "res:///test/") => true
+  (exists? "res:///test/te") => false
+  (exists? "res:///test/test.txt") => true)
+
+(facts "Listing"
+  (fact "listing root succeeds"
+    (ls "res:///") =not=> [])
+  (fact "listing test dir gives correct results"
+    (count (ls "res:///test/")) => 1
+    (:url (first (ls "res:///test"))) => (has-suffix "test/test.txt")
+    (:url (first (ls "res:///test/"))) => (has-suffix "test/test.txt"))
+  (fact "listing test file returns just the same file"
+    (count (ls "res:///test/test.txt")) => 1
+    (:url (first (ls "res:///test/test.txt"))) => (has-suffix "test/test.txt")))