add ledger-specific query route

Also add support for SPARQL protocol headers for specifying query graphs.

Author: dpetran

deps.edn

@@ -1,7 +1,7 @@
 {:deps {org.clojure/clojure    {:mvn/version "1.11.3"}
         org.clojure/core.async {:mvn/version "1.6.681"}
         com.fluree/db          {:git/url "https://github.com/fluree/db.git"
-                                :git/sha "f2bcf88ddf90c44ef50369da4edcb82f91f023e1"}
+                                :git/sha "f86dffe929d6f1294deb3ec22f4da58e6a989c32"}
         com.fluree/json-ld     {:git/url "https://github.com/fluree/json-ld.git"
                                 :git/sha "74083536c84d77f8cdd4b686b5661714010baad3"}
 

src/fluree/server/handler.clj

@@ -189,6 +189,16 @@
    :coercion   ^:replace  query-coercer
    :handler    #'ledger/query})
 
+(def ledger-query-endpoint
+  {:summary    "Endpoint for submitting queries to a specific ledger"
+   :parameters {:body QueryRequestBody
+                :path [:map [:ledger-alias :string]]}
+   :responses  {200 {:body QueryResponse}
+                400 {:body ErrorResponse}
+                500 {:body ErrorResponse}}
+   :coercion   ^:replace  query-coercer
+   :handler    #'ledger/query})
+
 (def history-endpoint
   {:summary    "Endpoint for submitting history queries"
    :parameters {:body HistoryQuery}
@@ -299,6 +309,12 @@
               (select-keys fluree-request-header-keys)
               (update-keys (fn [k] (keyword (subs k request-header-prefix-count)))))
 
+          ;; SPARQL protocol headers for graph specification
+          from         (get headers "default-graph-uri")
+          from-named   (get headers "named-graph-uri")
+          using        (get headers "using-graph-uri")
+          using-named  (get headers "using-named-graph-uri")
+
           max-fuel     (when max-fuel
                          (try (Integer/parseInt max-fuel)
                               (catch Exception e
@@ -371,6 +387,10 @@
                  max-fuel      (assoc :max-fuel max-fuel)
                  format        (assoc :format format)
                  output        (assoc :output output)
+                 from          (assoc :from from)
+                 from-named    (assoc :from from-named)
+                 using         (assoc :using using)
+                 using-named   (assoc :using using-named)
                  ledger        (assoc :ledger ledger)
                  policy        (assoc :policy policy)
                  policy-class  (assoc :policy-class policy-class)
@@ -561,6 +581,10 @@
    {:get  query-endpoint
     :post query-endpoint}])
 
+(def fluree-ledger-query-routes
+  ["/query/{*ledger-alias}"
+   {:post ledger-query-endpoint}])
+
 (def fluree-history-routes
   ["/history"
    {:get  history-endpoint
@@ -599,6 +623,7 @@
    :update       fluree-update-route
    :transact     fluree-transact-routes
    :query        fluree-query-routes
+   :ledger-query fluree-ledger-query-routes
    :history      fluree-history-routes
    :remote       fluree-remote-routes
    :subscription fluree-subscription-routes})

src/fluree/server/handlers/ledger.clj

@@ -5,11 +5,13 @@
             [fluree.server.handlers.shared :refer [defhandler deref!] :as shared]))
 
 (defhandler query
-  [{:keys [fluree/conn fluree/opts] {:keys [body]} :parameters :as _req}]
+  [{:keys [fluree/conn fluree/opts] {:keys [body path]} :parameters :as _req}]
   (let [query (or (::handler/query body) body)
+        ;; supply ledger-alias from path params if not overridden by a header
+        opts* (update opts :ledger #(or % (:ledger-alias path)))
         {:keys [status result] :as query-response}
-        (deref! (fluree/query-connection conn query opts))]
-    (log/debug "query handler received query:" query opts)
+        (deref! (fluree/query-connection conn query opts*))]
+    (log/debug "query handler received query:" query opts*)
     (shared/with-tracking-headers {:status status, :body result}
       query-response)))
 

test/fluree/server/integration/sparql_test.clj

@@ -2,7 +2,7 @@
   (:require [clojure.string :as str]
             [clojure.test :refer [deftest is testing use-fixtures]]
             [fluree.db.util.json :as json]
-            [fluree.server.integration.test-system
+            [fluree.server.integration.test-system :as test-system
              :refer [api-post create-rand-ledger run-test-server sparql-headers
                      sparql-results-headers sparql-update-headers]]))
 
@@ -63,3 +63,34 @@
               "@graph" [{"@id" "ex:query-sparql-test"
                          "foo:name" ["query-sparql-test"]}]}
              (-> rdf-res :body (json/parse false)))))))
+
+(deftest sparql-federated-query
+  (let [ledger-name "test-federated-query"
+        service     (str "http://localhost:" @test-system/api-port "/fluree/query/" ledger-name)
+
+        txn-req     {"ledger" ledger-name
+                     "@context" {"ex" "http://example.com/"}
+                     "insert" (mapv #(do {"@id" (str "ex:" %)
+                                          "@type" (if (odd? %) "ex:Odd" "ex:Even")
+                                          "ex:name" (str "name" %)
+                                          "ex:num" [(dec %) % (inc %)]
+                                          "ex:ref" {"@id" (str "ex:" (inc %))}})
+                                    (range 10))}
+        txn-res (api-post :create {:body (json/stringify txn-req) :headers test-system/json-headers})
+
+        service-q (str/join "\n" ["PREFIX ex: <http://example.com/>"
+                                  "SELECT ?name ?type"
+                                  (str "FROM <" ledger-name ">")
+                                  "WHERE { ?s a ex:Even ; ex:ref ?ref . "
+                                  (str "SERVICE <" service "> { ?ref ex:name ?name ; a ?type . }")
+                                  "}"])
+        service-res (api-post :query {:body service-q :headers sparql-headers})]
+    (is (= 201 (:status txn-res)))
+    (is (= 200 (:status service-res)))
+    (testing "federated query can join across local and remote graphs"
+      (is (= [["name1" "ex:Odd"]
+              ["name3" "ex:Odd"]
+              ["name5" "ex:Odd"]
+              ["name7" "ex:Odd"]
+              ["name9" "ex:Odd"]]
+             (-> service-res :body (json/parse false)))))))