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--- tanszek:oktatas:iss_t:json-rpc [2026/03/01 17:06] – [JSON-RPC Server (Python + Flask)] knehez
+++ tanszek:oktatas:iss_t:json-rpc [2026/03/01 17:27] (current) – [JSON-RPC Client (Python)] knehez
@@ Line 24: / Line 24: @@
 A JSON-RPC request is a JSON object with the following fields:
-jsonrpc – must be "2.0"
+  * **jsonrpc** – must be "2.0"
+  * **method** – name of the remote method
-method – name of the remote method
+  * **params** – parameters (optional)
+  * **id** – request identifier (used to match response)
-params – parameters (optional)
-id – request identifier (used to match response)
 Example request:
@@ Line 78: / Line 75: @@
 Create a file: //server.py//
-<sxh python> from flask import Flask, request, jsonify
+<sxh python>
+from flask import Flask, request, jsonify
-app = Flask(name)
+app = Flask(__name__)
-Available RPC methods
+# available RPC methods
 def add(a, b):
-return a + b
+    return a + b
 def subtract(a, b):
-return a - b
+    return a - b
 methods = {
-"add": add,
+    "add": add,
-"subtract": subtract
+    "subtract": subtract,
 }
 @app.route("/rpc", methods=["POST"])
 def rpc():
-data = request.get_json()
+    data = request.get_json()
-if data.get("jsonrpc") != "2.0":
+    if data.get("jsonrpc") != "2.0":
-    return jsonify({
+        return jsonify(
-        "jsonrpc": "2.0",
+            {
-        "error": {"code": -32600, "message": "Invalid Request"},
+                "jsonrpc": "2.0",
-        "id": data.get("id")
+                "error": {"code": -32600, "message": "Invalid Request"},
-    })
+                "id": data.get("id"),
+            }
+        )
-method_name = data.get("method")
+    method_name = data.get("method")
-params = data.get("params", [])
+    params = data.get("params", [])
-request_id = data.get("id")
+    request_id = data.get("id")
-if method_name not in methods:
+    if method_name not in methods:
-    return jsonify({
+        return jsonify(
-        "jsonrpc": "2.0",
+            {
-        "error": {"code": -32601, "message": "Method not found"},
+                "jsonrpc": "2.0",
-        "id": request_id
+                "error": {"code": -32601, "message": "Method not found"},
-    })
+                "id": request_id,
+            }
+        )
-try:
+    try:
-    result = methods[method_name](*params)
+        result = methods[method_name](*params)
-    return jsonify({
+        return jsonify(
-        "jsonrpc": "2.0",
+            {
-        "result": result,
+                "jsonrpc": "2.0",
-        "id": request_id
+                "result": result,
-    })
+                "id": request_id,
-except Exception as e:
+            }
-    return jsonify({
+        )
-        "jsonrpc": "2.0",
+    except Exception as e:
-        "error": {"code": -32603, "message": str(e)},
+        return jsonify(
-        "id": request_id
+            {
-    })
+                "jsonrpc": "2.0",
+                "error": {"code": -32603, "message": str(e)},
+                "id": request_id,
+            }
+        )
+if __name__ == "__main__":
+    app.run(port=5000)
-if name == "main":
-app.run(port=5000)
 </sxh>
@@ Line 138: / Line 149: @@
 <code bash> python server.py </code>
+===== JSON-RPC Client (Python) =====
+Create a file: //client.py//
+<sxh python>
+import requests import json
+url = "http://localhost:5000/rpc"
+payload = {
+  "jsonrpc": "2.0",
+  "method": "add",
+  "params": [10, 15],
+  "id": 1
+}
+response = requests.post(url, json=payload)
+print("Status:", response.status_code)
+print("Response:", response.json())
+</sxh>
+Expected output:
+<code> Status: 200 Response: {'jsonrpc': '2.0', 'result': 25, 'id': 1} </code>
+==== Error Codes in JSON-RPC 2.0 ====
+^ Code ^ Meaning ^
+| -32700 | Parse error |
+| -32600 | Invalid Request |
+| -32601 | Method not found |
+| -32602 | Invalid params |
+| -32603 | Internal error |