Enable gzip compression in nginx for RDF and JSON content types (#290)

* Enable gzip compression in nginx for RDF and JSON content types

Adds gzip_types covering application/json, SPARQL results, RDF serializations
(Turtle, RDF/XML, LD+JSON, TriG, N-Quads, N-Triples), XML, CSS, JS, and SVG.
Primarily reduces client.xsl.sef.json transfer size from ~11.8MB to ~2-3MB.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* Add gzip HTTP tests for SEF file and RDF/XML response

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* Fix gzip HTTP tests: use -D - to avoid binary body, add owner cert for RDF/XML

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* nginx conf fix

* Fix gzip RDF/XML test: create item and append data instead of testing root container

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: namedgraph

docker-compose.yml

@@ -193,6 +193,25 @@ configs:
 
           client_max_body_size ${MAX_CONTENT_LENGTH:-2097152};
 
+          gzip on;
+          gzip_proxied any;
+          gzip_types
+              application/json
+              application/ld+json
+              application/rdf+xml
+              application/sparql-results+json
+              application/sparql-results+xml
+              application/trig
+              application/n-quads
+              application/n-triples
+              application/xml
+              text/turtle
+              text/css
+              text/javascript
+              application/javascript
+              image/svg+xml;
+          gzip_min_length 1024;
+
           # server with optional client cert authentication
           server {
               listen 8443 ssl;

http-tests/misc/gzip-rdfxml.sh

@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+initialize_dataset "$END_USER_BASE_URL" "$TMP_END_USER_DATASET" "$END_USER_ENDPOINT_URL"
+initialize_dataset "$ADMIN_BASE_URL" "$TMP_ADMIN_DATASET" "$ADMIN_ENDPOINT_URL"
+purge_cache "$END_USER_VARNISH_SERVICE"
+purge_cache "$ADMIN_VARNISH_SERVICE"
+purge_cache "$FRONTEND_VARNISH_SERVICE"
+
+# Test that nginx gzip compression is active for RDF/XML dynamic content.
+# Create an item, append enough data to exceed gzip_min_length, then retrieve it as RDF/XML.
+
+add-agent-to-group.sh \
+  -f "$OWNER_CERT_FILE" \
+  -p "$OWNER_CERT_PWD" \
+  --agent "$AGENT_URI" \
+  "${ADMIN_BASE_URL}acl/groups/writers/"
+
+item=$(create-item.sh \
+  -f "$AGENT_CERT_FILE" \
+  -p "$AGENT_CERT_PWD" \
+  -b "$END_USER_BASE_URL" \
+  --title "Gzip test item" \
+  --slug "gzip-test" \
+  --container "$END_USER_BASE_URL")
+
+printf '@prefix ex: <http://example.org/> .\n
+<> ex:prop1 "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore." ;\n
+   ex:prop2 "Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo." ;\n
+   ex:prop3 "Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur." ;\n
+   ex:prop4 "Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est." .\n' \
+| post.sh \
+  -f "$AGENT_CERT_FILE" \
+  -p "$AGENT_CERT_PWD" \
+  -t "text/turtle" \
+  "$item"
+
+response=$(curl -k -s -D - -o /dev/null \
+  -H "Accept-Encoding: gzip" \
+  -H "Accept: application/rdf+xml" \
+  -E "$AGENT_CERT_FILE":"$AGENT_CERT_PWD" \
+  "$item")
+
+if ! echo "$response" | grep -qi "Content-Encoding: gzip"; then
+  echo "Content-Encoding: gzip not found on RDF/XML response"
+  exit 1
+fi
+
+if ! echo "$response" | grep -q "HTTP/.* 200"; then
+  echo "RDF/XML request did not return 200 OK"
+  exit 1
+fi

http-tests/misc/gzip-sefjson.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Test that nginx gzip compression is active for static JSON (SEF file)
+
+response=$(curl -k -s -D - -o /dev/null \
+  -H "Accept-Encoding: gzip" \
+  "${END_USER_BASE_URL}static/com/atomgraph/linkeddatahub/xsl/client.xsl.sef.json")
+
+if ! echo "$response" | grep -qi "Content-Encoding: gzip"; then
+  echo "Content-Encoding: gzip not found on client.xsl.sef.json"
+  exit 1
+fi
+
+if ! echo "$response" | grep -q "HTTP/.* 200"; then
+  echo "client.xsl.sef.json did not return 200 OK"
+  exit 1
+fi