Add Python as a language

build.gradle.kts

@@ -22,6 +22,14 @@ dependencies {
 	implementation("org.springframework.boot:spring-boot-starter-data-jpa")
 	implementation("org.springframework.boot:spring-boot-starter-security")
 	implementation("org.springframework.boot:spring-boot-starter-webmvc")
+
+	compileOnly("org.projectlombok:lombok:1.18.46")
+	annotationProcessor("org.projectlombok:lombok:1.18.46")
+
+	testCompileOnly("org.projectlombok:lombok:1.18.46")
+	testAnnotationProcessor("org.projectlombok:lombok:1.18.46")
+
+
 	runtimeOnly("com.h2database:h2")
 	testImplementation("org.springframework.boot:spring-boot-starter-data-jpa-test")
 	testImplementation("org.springframework.boot:spring-boot-starter-security-test")

docker-compose.yml

@@ -4,9 +4,13 @@ services:
     ports:
       - "8080:8080"
 
+  runner:
+    build: ./runner
+
   frontend:
     build: ./frontend
     ports:
       - "80:80"
     depends_on:
       - backend
+      - runner

frontend/nginx.conf

@@ -10,6 +10,11 @@ server {
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     }
 
+    location /runner/ {
+        proxy_pass http://runner:5000/;
+    }
+
+
     location / {
         try_files $uri /index.html;
     }

frontend/src/pages/ChallengePage.jsx

@@ -3,8 +3,16 @@ import { useParams, Link } from 'react-router-dom'
 import Editor from '@monaco-editor/react'
 import api from '../api/axios'
 
+function sortKeys(val) {
+  if (Array.isArray(val)) return val.map(sortKeys)
+  if (val && typeof val === 'object') {
+    return Object.fromEntries(Object.keys(val).sort().map(k => [k, sortKeys(val[k])]))
+  }
+  return val
+}
+
 function deepEqual(a, b) {
-  return JSON.stringify(a) === JSON.stringify(b)
+  return JSON.stringify(sortKeys(a)) === JSON.stringify(sortKeys(b))
 }
 
 function sortBySource(arr) {
@@ -56,6 +64,17 @@ export default function ChallengePage() {
   const [running, setRunning] = useState(false)
   const [results, setResults] = useState(null)
   const codeRef = useRef('')
+  const [language, setLanguage] = useState('javascript')
+  const availableLanguages = challenge ? ['javascript',
+    ...challenge.variants.map(v => v.language)]
+    : ['javascript']
+  useEffect(() => {
+    if (!challenge) return
+    const starterCode = language === 'javascript'
+      ? challenge.starterCode
+      : challenge.variants.find(v => v.language === language)?.starterCode ?? ''
+    codeRef.current = starterCode
+  }, [language, challenge])
 
   useEffect(() => {
     api.get(`/challenges/${id}`)
@@ -77,7 +96,27 @@ export default function ChallengePage() {
     for (const tc of visibleTests) {
       const input = JSON.parse(tc.inputJson)
       const expected = JSON.parse(tc.expectedJson)
-      const response = await runWorker(challenge.harnessCode, codeRef.current, input)
+      let response
+
+      if (language === 'javascript') {
+        response = await runWorker(challenge.harnessCode, codeRef.current, input)
+      } else {
+        const variant = challenge.variants.find(v => v.language === language)
+        try {
+          const res = await fetch('/runner/run', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({
+              code: codeRef.current,
+              input,
+              harnessTemplate: variant.harnessTemplate,
+            }),
+          })
+          response = await res.json()
+        } catch (err) {
+          response = { ok: false, error: err.message }
+        }
+      }
 
       if (!response.ok) {
         testResults.push({ description: tc.description, pass: false, actual: null, expected, error: response.error })
@@ -97,7 +136,7 @@ export default function ChallengePage() {
         code: codeRef.current,
         status: 'PASS',
         testResults: JSON.stringify(testResults),
-      }).catch(() => {})
+      }).catch(() => { })
     }
   }
 
@@ -172,11 +211,42 @@ export default function ChallengePage() {
 
       {/* Right column */}
       <div style={{ width: '40%', display: 'flex', flexDirection: 'column', overflow: 'hidden' }}>
+
+        <div style={{
+          padding: '8px 16px',
+          borderBottom: '1px solid #2d3748', display: 'flex', gap: 8
+        }}>
+          {availableLanguages.map(lang => (
+            <button
+              key={lang}
+              onClick={() => setLanguage(lang)}
+              style={{
+                padding: 'rpx 12px',
+                fontSize: 12,
+                background: language === lang ?
+                  '#3182ce' : 'transparent',
+                color: language === lang ? '#fff' : '#718096',
+                border: '1px solid #2d3748',
+                borderRadius: 4,
+                cursor: 'pointer',
+              }}
+            >
+              {lang === 'javascript' ? 'JavaScript' : 'Python'}
+            </button>
+          ))}
+        </div>
+
+
         <div style={{ flex: 1, minHeight: 0 }}>
           <Editor
+            key={language}
             height="100%"
-            defaultLanguage="javascript"
-            defaultValue={challenge.starterCode}
+            defaultLanguage={language}
+            defaultValue={
+              language === 'javascript'
+                ? challenge.starterCode
+                : challenge.variants.find(v => v.language === language)?.starterCode ?? ''
+            }
             theme="vs-dark"
             onChange={value => { codeRef.current = value ?? '' }}
             options={{

runner/Dockerfile

@@ -0,0 +1,7 @@
+FROM python:3.12-slim
+WORKDIR /app
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+COPY app.py .
+EXPOSE 5000
+CMD ["python", "app.py"]

runner/app.py

@@ -0,0 +1,45 @@
+import json
+import os
+import subprocess
+import tempfile
+from flask import Flask, request, jsonify
+
+app = Flask(__name__)
+
+@app.route('/run', methods=['POST'])
+def run_code():
+    data = request.get_json()
+    code = data.get('code', '')
+    input_data = data.get('input', {})
+    harness_template = data.get('harnessTemplate', '')
+
+    script = harness_template.replace('{USER_CODE}', code)
+
+    tmp_path = None
+    try:
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.py', delete=False, dir='/tmp') as f:
+            f.write(script)
+            tmp_path = f.name
+
+        result = subprocess.run(['python3', tmp_path],
+                                 input=json.dumps(input_data), 
+                                 capture_output=True, text=True, 
+                                 timeout=5, cwd='/tmp',)
+
+        if result.returncode != 0:
+            return jsonify({'ok': False, 'error': result.stderr.strip()})
+
+        return jsonify(json.loads(result.stdout))
+
+    except subprocess.TimeoutExpired:
+        return jsonify({'ok': False, 'error': 'Timeout (5s)'})
+    except json.JSONDecodeError:
+        return jsonify({'ok': False, 'error': 'Runner output was not valid JSON'})
+    except Exception as e:
+        return jsonify({'ok': False, 'error': str(e)})
+    finally:
+        if tmp_path and os.path.exists(tmp_path):
+            os.unlink(tmp_path)
+
+if __name__ == '__main__':
+    app.run(host='0.0.0.0', port=5000)

runner/requirements.txt

@@ -0,0 +1 @@
+flask==3.1.0

src/main/java/no/hvl/schemalab/DataSeeder.java

@@ -3,26 +3,67 @@
 import no.hvl.schemalab.model.*;
 import no.hvl.schemalab.repository.AppUserRepository;
 import no.hvl.schemalab.repository.ChallengeRepository;
+import no.hvl.schemalab.repository.ChallengeVariantRepository;
+
 import org.springframework.boot.CommandLineRunner;
 import org.springframework.security.crypto.password.PasswordEncoder;
 import org.springframework.stereotype.Component;
 
+import lombok.Data;
+
 import java.util.List;
 
 @Component
+@Data
 public class DataSeeder implements CommandLineRunner {
 
   private final ChallengeRepository challengeRepository;
+  private final ChallengeVariantRepository challengeVariantRepository;
   private final AppUserRepository appUserRepository;
   private final PasswordEncoder passwordEncoder;
 
-  public DataSeeder(ChallengeRepository challengeRepository,
-      AppUserRepository appUserRepository,
-      PasswordEncoder passwordEncoder) {
-    this.challengeRepository = challengeRepository;
-    this.appUserRepository = appUserRepository;
-    this.passwordEncoder = passwordEncoder;
-  }
+  private final String MATCHING_HARNESS_PY = "import json, sys\n" + //
+      "input_data = json.loads(sys.stdin.read())\n" + //
+      "\n" + //
+      "{USER_CODE}\n" + //
+      "\n" + //
+      "try:\n" + //
+      "    result = match_schemas(input_data['schemaA'], input_data['schemaB'])\n" + //
+      "    print(json.dumps({\"ok\": True, \"result\": result}))\n" + //
+      "except Exception as e:\n" + //
+      "    print(json.dumps({\"ok\": False, \"error\": str(e)}))";
+
+  private final String VERSIONING_HARNESS_PY = "import json, sys\n" + //
+      "input_data = json.loads(sys.stdin.read())\n" + //
+      "\n" + //
+      "{USER_CODE}\n" + //
+      "\n" + //
+      "try:\n" + //
+      "    result = migrate(input_data['record'])\n" + //
+      "    print(json.dumps({\"ok\": True, \"result\": result}))\n" + //
+      "except Exception as e:\n" + //
+      "    print(json.dumps({\"ok\": False, \"error\": str(e)}))";
+
+  private final String MATCHING_TEMPLATE_PY = """
+        #
+        # Match fields from schemaA to schemaB.
+        # @param {Object} schemaA - JSON Schema object
+        # @param {Object} schemaB - JSON Schema object
+        # @returns [<{source: string, target: string}>]
+        #
+      def match_schemas(schema_a, schema_b):
+          return []
+      """;
+
+  private final String VERSIONING_TEMPLATE_PY = """
+        #
+        # Migrate a record from schema v1 to schema v2.
+        # @param record - A v1 record instance
+        # @returns {Object} - A v2 record instance
+        #
+      def migrate(record):
+        return {}
+      """;;
 
   @Override
   public void run(String... args) {
@@ -37,6 +78,18 @@ public void run(String... args) {
     }
   }
 
+  /// HELPER METHODS
+
+  private void addPythonVariant(Challenge challenge, String starterCode, String harnessTemplate) {
+    ChallengeVariant v = new ChallengeVariant();
+    v.setChallenge(challenge);
+    v.setLanguage("python");
+    v.setStarterCode(starterCode);
+    v.setHarnessTemplate(harnessTemplate);
+    challengeVariantRepository.save(v);
+  }
+
+  //
   private void seedDevUser() {
     if (appUserRepository.findByUsername("dev").isEmpty()) {
       AppUser dev = new AppUser();
@@ -169,6 +222,8 @@ function matchSchemas(schemaA, schemaB) {
     c.setTestCases(List.of(visible, hidden));
 
     challengeRepository.save(c);
+
+    addPythonVariant(c, MATCHING_TEMPLATE_PY, MATCHING_HARNESS_PY);
   }
 
   private void seedChallenge2() {
@@ -264,6 +319,8 @@ record TestData(String fullName, String firstName, String lastName, String id, S
     c.setTestCases(testCases);
 
     challengeRepository.save(c);
+
+    addPythonVariant(c, VERSIONING_TEMPLATE_PY, VERSIONING_HARNESS_PY);
   }
 
   private void seedChallenge3() {
@@ -385,6 +442,8 @@ function matchSchemas(schemaA, schemaB) {
     c.setTestCases(List.of(visible, hidden));
 
     challengeRepository.save(c);
+
+    addPythonVariant(c, MATCHING_TEMPLATE_PY, MATCHING_HARNESS_PY);
   }
 
   private void seedChallenge4() {
@@ -485,6 +544,8 @@ record TestData(String id, String name, String street, String city, String posta
     c.setTestCases(testCases);
 
     challengeRepository.save(c);
+
+    addPythonVariant(c, VERSIONING_TEMPLATE_PY, VERSIONING_HARNESS_PY);
   }
 
   private void seedChallenge5() {
@@ -631,6 +692,8 @@ function matchSchemas(schemaA, schemaB) {
     c.setTestCases(List.of(visible, hidden));
 
     challengeRepository.save(c);
+
+    addPythonVariant(c, MATCHING_TEMPLATE_PY, MATCHING_HARNESS_PY);
   }
 
   private void seedChallenge6() {
@@ -730,5 +793,7 @@ record TestData(String empId, String fullName, String firstName, String lastName
     c.setTestCases(testCases);
 
     challengeRepository.save(c);
+
+    addPythonVariant(c, VERSIONING_TEMPLATE_PY, VERSIONING_HARNESS_PY);
   }
 }