feature: add support for binary resource download (fixes #2108)

.github/scripts/read-binary-content-not-found.sh

@@ -0,0 +1,20 @@
+#!/bin/bash -e
+
+# This script queries the server for a non-existent binary resource
+# and verifies that we get the 404 error message.
+
+SCRIPT_DIR="$(dirname "$(readlink -f "$0")")"
+. "$SCRIPT_DIR/util.sh"
+
+BASE="http://localhost:8080/fhir"
+
+RANDOM_ID="$(uuidgen | tr '[:upper:]' '[:lower:]')"
+
+# Attempt to retrieve the Binary resource by ID
+echo "Verifying that the Binary resource with ID '$RANDOM_ID' does not exist."
+
+# Perform a GET request to retrieve the Binary resource by ID
+STATUS_CODE=$(curl -s -H "Accept: application/pdf" -o /dev/null -w '%{response_code}' "$BASE/Binary/$RANDOM_ID")
+
+# Test that the response code is 404 (Not Found), indicating the resource doesn't exist
+test "GET response code for Binary resource" "$STATUS_CODE" "404"

.github/scripts/read-binary-content.sh

@@ -0,0 +1,34 @@
+#!/bin/bash -e
+
+# This script creates a binary resource and verifies that its binary content
+# can be read.
+
+SCRIPT_DIR="$(dirname "$(readlink -f "$0")")"
+. "$SCRIPT_DIR/util.sh"
+
+BASE="http://localhost:8080/fhir"
+
+# 10 KiB of random data, base64 encoded
+DATA="$(openssl rand -base64 10240 | tr -d '\n')"
+
+binary() {
+cat <<END
+{
+  "resourceType": "Binary",
+  "contentType": "application/pdf",
+  "data": "$DATA"
+}
+END
+}
+
+# Create a Binary resource that contains that data, and get its ID
+ID=$(curl -s -H 'Content-Type: application/fhir+json' -d "$(binary)" "$BASE/Binary" | jq -r .id)
+
+echo "Created Binary resource that contains the Random Data, with ID: $ID"
+
+# Retrieve the Binary resource, and Base64 encode it so it can be safely handled by Bash
+BASE64_ENCODED_BINARY_RESOURCE=$(curl -s -H 'Accept: application/pdf' "$BASE/Binary/$ID" | base64 | tr -d '\n')
+
+echo "Binary data retrieved. Verifying content..."
+
+test "Base64 encoding of Resource data" "$DATA" "$BASE64_ENCODED_BINARY_RESOURCE"

.github/workflows/build.yml

@@ -1059,6 +1059,12 @@ jobs:
     - name: Search _tag
       run: .github/scripts/search-tag.sh
 
+    - name: Binary Download - not found
+      run: .github/scripts/read-binary-content-not-found.sh
+
+    - name: Binary Download - found
+      run: .github/scripts/read-binary-content.sh
+
     - name: Conditional Delete - Check Referential Integrity Violated
       run: .github/scripts/conditional-delete-type/check-referential-integrity-violated.sh
 

modules/rest-api/src/blaze/rest_api/routes.clj

@@ -64,6 +64,7 @@
    :compile (fn [{:keys [response-type] :response-type.json/keys [opts]} _]
               (condp = response-type
                 :json (output/wrap-output opts)
+                :binary fhir-output/wrap-binary-output
                 :none identity
                 fhir-output/wrap-output))})
 
@@ -169,6 +170,8 @@
           (cond->
            {:name (keyword name "instance")
             :conflicting true}
+            (= name "Binary")
+            (assoc :response-type :binary)
             (contains? interactions :read)
             (assoc :get {:interaction "read"
                          :middleware [[wrap-db node db-sync-timeout]]

modules/rest-api/src/blaze/rest_api/spec.clj

@@ -102,7 +102,7 @@
   boolean?)
 
 (s/def ::operation/response-type
-  #{:json})
+  #{:json :binary})
 
 (s/def ::operation/resource-types
   (s/coll-of string?))

modules/rest-util/src/blaze/middleware/fhir/output.clj

@@ -7,6 +7,7 @@
   (:require
    [blaze.anomaly :as ba]
    [blaze.fhir.spec :as fhir-spec]
+   [blaze.fhir.spec.type :as type]
    [blaze.handler.util :as handler-util]
    [clojure.data.xml :as xml]
    [clojure.java.io :as io]
@@ -15,7 +16,8 @@
    [ring.util.response :as ring]
    [taoensso.timbre :as log])
   (:import
-   [java.io ByteArrayOutputStream]))
+   [java.io ByteArrayOutputStream]
+   [java.util Base64]))
 
 (set! *warn-on-reflection* true)
 
@@ -49,6 +51,21 @@
   (with-open [_ (prom/timer generate-duration-seconds "xml")]
     (generate-xml* body)))
 
+(defn- generate-binary** [body]
+  (when (:data body)
+    (.decode (Base64/getDecoder) ^String (type/value (:data body)))))
+
+(defn- generate-binary* [body]
+  (try
+    (generate-binary** body)
+    (catch Throwable e
+      (generate-binary** (handler-util/operation-outcome (ba/anomaly e))))))
+
+(defn- generate-binary [body]
+  (log/trace "generate binary")
+  (with-open [_ (prom/timer generate-duration-seconds "binary")]
+    (generate-binary* body)))
+
 (defn- encode-response-json [{:keys [body] :as response} content-type]
   (cond-> response body (-> (update :body generate-json)
                             (ring/content-type content-type))))
@@ -57,6 +74,14 @@
   (cond-> response body (-> (update :body generate-xml)
                             (ring/content-type content-type))))
 
+(defn- binary-content-type [body]
+  (or (-> body :contentType type/value)
+      "application/octet-stream"))
+
+(defn- encode-response-binary [{:keys [body] :as response}]
+  (cond-> response body (-> (update :body generate-binary)
+                            (ring/content-type (binary-content-type body)))))
+
 (defn- format-key [format]
   (condp = format
     "application/fhir+json" :fhir+json
@@ -96,3 +121,15 @@
   ([handler opts]
    (fn [request respond raise]
      (handler request #(respond (handle-response opts request %)) raise))))
+
+(defn handle-binary-response [request response]
+  (case (request-format request)
+    :fhir+json (encode-response-json response "application/fhir+json;charset=utf-8")
+    :fhir+xml (encode-response-xml response "application/fhir+xml;charset=utf-8")
+    (encode-response-binary response)))
+
+(defn wrap-binary-output
+  "Middleware to output binary resources."
+  [handler]
+  (fn [request respond raise]
+    (handler request #(respond (handle-binary-response request %)) raise)))

modules/rest-util/test/blaze/middleware/fhir/output_test.clj

@@ -1,9 +1,11 @@
 (ns blaze.middleware.fhir.output-test
   (:require
+   [blaze.byte-string :as bs]
    [blaze.fhir.spec :as fhir-spec]
    [blaze.fhir.spec-spec]
+   [blaze.fhir.spec.type :as type]
    [blaze.fhir.test-util]
-   [blaze.middleware.fhir.output :refer [wrap-output]]
+   [blaze.middleware.fhir.output :refer [wrap-binary-output wrap-output]]
    [blaze.module.test-util.ring :refer [call]]
    [blaze.test-util :as tu]
    [clojure.data.xml :as xml]
@@ -27,17 +29,47 @@
    (fn [_ respond _]
      (respond (ring/response {:fhir/type :fhir/Patient :id "0"})))))
 
+(defn- special-resource-handler [resource]
+  (wrap-output
+   (fn [_ respond _]
+     (respond (ring/response resource)))))
+
+(defn- binary-resource-handler-200
+  "A handler which uses the binary middleware and
+  returns a binary resource."
+  [{:keys [content-type data]}]
+  (wrap-binary-output
+   (fn [_ respond _]
+     (respond
+      (ring/response
+       (cond-> {:fhir/type :fhir/Binary}
+         data (assoc :data (type/base64Binary data))
+         content-type (assoc :contentType (type/code content-type))))))))
+
+(def ^:private binary-resource-handler-no-body
+  "A handler which uses the binary middleware and
+  returns a response with 200 and no body."
+  (wrap-binary-output
+   (fn [_ respond _]
+     (respond (ring/status 200)))))
+
 (def ^:private resource-handler-304
   "A handler which returns a 304 Not Modified response."
   (wrap-output
    (fn [_ respond _]
      (respond (ring/status 304)))))
 
-(defn- special-resource-handler [resource]
-  (wrap-output
+(defn- common-handler [wrapper-middleware resource]
+  (wrapper-middleware
    (fn [_ respond _]
      (respond (ring/response resource)))))
 
+(defn- special-resource-handler [resource]
+  (common-handler wrap-output resource))
+
+(defn- binary-resource-handler [resource]
+  (common-handler wrap-binary-output resource))
+
 (defn- parse-json [body]
   (fhir-spec/conform-json (fhir-spec/parse-json body)))
 
@@ -140,5 +172,62 @@
       [:headers "Content-Type"] := "application/fhir+xml;charset=utf-8"
       [:body parse-xml :issue 0 :diagnostics] := "Invalid white space character (0x1e) in text to output (in xml 1.1, could output as a character entity)")))
 
+(deftest binary-resource-test
+  (testing "returning the resource"
+    (testing "JSON"
+      (given (call (binary-resource-handler-200 {:content-type "text/plain" :data "MTA1NjE0Cg=="}) {:headers {"accept" "application/fhir+json"}})
+        :status := 200
+        [:headers "Content-Type"] := "application/fhir+json;charset=utf-8"
+        [:body parse-json] := {:fhir/type :fhir/Binary
+                               :contentType #fhir/code"text/plain"
+                               :data #fhir/base64Binary"MTA1NjE0Cg=="}))
+
+    (testing "XML"
+      (given (call (binary-resource-handler-200 {:content-type "text/plain" :data "MTA1NjE0Cg=="}) {:headers {"accept" "application/fhir+xml"}})
+        :status := 200
+        [:headers "Content-Type"] := "application/fhir+xml;charset=utf-8"
+        [:body parse-xml] := {:fhir/type :fhir/Binary
+                              :contentType #fhir/code"text/plain"
+                              :data #fhir/base64Binary"MTA1NjE0Cg=="})))
+
+  (testing "returning the data"
+    (testing "with content type"
+      (given (call (binary-resource-handler-200 {:content-type "text/plain" :data "MTA1NjE0Cg=="}) {:headers {"accept" "text/plain"}})
+        :status := 200
+        [:headers "Content-Type"] := "text/plain"
+        [:body bs/from-byte-array] := #blaze/byte-string"3130353631340A"))
+
+    (testing "without content type"
+      (given (call (binary-resource-handler-200 {:content-type nil :data "MTA1NjE0Cg=="}) {:headers {"accept" "text/plain"}})
+        :status := 200
+        [:headers "Content-Type"] := "application/octet-stream"
+        [:body bs/from-byte-array] := #blaze/byte-string"3130353631340A")))
+
+  (testing "without data"
+    (testing "with content type"
+      (given (call (binary-resource-handler-200 {:content-type "text/plain"}) {:headers {"accept" "text/plain"}})
+        :status := 200
+        [:headers "Content-Type"] := "text/plain"
+        :body := nil))
+
+    (testing "without content type"
+      (given (call (binary-resource-handler-200 {:content-type nil}) {:headers {"accept" "text/plain"}})
+        :status := 200
+        [:headers "Content-Type"] := "application/octet-stream"
+        :body := nil)))
+
+  (testing "without body at all"
+    (given (call binary-resource-handler-no-body {:headers {"accept" "text/plain"}})
+      :status := 200
+      [:headers "Content-Type"] := nil
+      :body := nil))
+
+  (testing "failing binary emit"
+    (given (call (binary-resource-handler {:fhir/type :fhir/Patient :id "0" :gender #fhir/code"foo\u001Ebar"}) {:headers {"accept" "text/plain"}})
+      :status := 500
+      [:headers "Content-Type"] := "application/fhir+xml;charset=utf-8"
+      [:body parse-xml :fhir/type] := :fhir/OperationOutcome
+      [:body parse-xml :issue 0 :diagnostics] := "Invalid white space character (0x1e) in text to output (in xml 1.1, could output as a character entity)")))
+
 (deftest not-acceptable-test
   (is (nil? (call resource-handler-200 {:headers {"accept" "text/plain"}}))))