API Client Tester Waruna834

API Client & Tester

Skill by ara.so — Devtools Skills collection.

Overview

API Client & Tester is a complete API testing tool for REST, GraphQL, and WebSocket protocols. It provides a lightweight alternative to Postman with support for multiple HTTP methods, authentication strategies, request collections, and import/export functionality.

Installation

From Source

git clone https://github.com/waruna834/API_Client___Tester.git
cd API_Client___Tester
pip install -r requirements.txt
python main.py

Requirements

• Python 3.7+
• Windows 10/11 (64-bit)
• Dependencies managed via requirements.txt

Core Components

HTTP Client

The tool supports standard HTTP methods with authentication:

import requests
import json

class APIClient:
    def __init__(self, base_url=""):
        self.base_url = base_url
        self.headers = {}
        self.auth = None
    
    def set_auth(self, auth_type, credentials):
        """Set authentication for requests"""
        if auth_type == "basic":
            from requests.auth import HTTPBasicAuth
            self.auth = HTTPBasicAuth(credentials['username'], credentials['password'])
        elif auth_type == "bearer":
            self.headers['Authorization'] = f"Bearer {credentials['token']}"
        elif auth_type == "api_key":
            self.headers[credentials['key_name']] = credentials['key_value']
    
    def request(self, method, endpoint, **kwargs):
        """Send HTTP request"""
        url = f"{self.base_url}{endpoint}"
        kwargs.setdefault('headers', {}).update(self.headers)
        if self.auth:
            kwargs['auth'] = self.auth
        
        response = requests.request(method, url, **kwargs)
        return {
            'status_code': response.status_code,
            'headers': dict(response.headers),
            'body': response.text,
            'json': response.json() if response.headers.get('content-type', '').startswith('application/json') else None
        }

# Usage
client = APIClient(base_url="https://api.example.com")
client.set_auth("bearer", {"token": os.getenv("API_TOKEN")})

response = client.request("GET", "/users", params={"page": 1})
print(f"Status: {response['status_code']}")
print(f"Data: {response['json']}")

GraphQL Support

class GraphQLClient:
    def __init__(self, endpoint, headers=None):
        self.endpoint = endpoint
        self.headers = headers or {}
    
    def query(self, query, variables=None):
        """Execute GraphQL query"""
        payload = {
            'query': query,
            'variables': variables or {}
        }
        
        response = requests.post(
            self.endpoint,
            json=payload,
            headers=self.headers
        )
        
        result = response.json()
        if 'errors' in result:
            raise Exception(f"GraphQL errors: {result['errors']}")
        
        return result['data']
    
    def mutation(self, mutation, variables=None):
        """Execute GraphQL mutation"""
        return self.query(mutation, variables)

# Usage
gql_client = GraphQLClient(
    endpoint="https://api.example.com/graphql",
    headers={"Authorization": f"Bearer {os.getenv('GRAPHQL_TOKEN')}"}
)

query = """
query GetUser($id: ID!) {
    user(id: $id) {
        id
        name
        email
    }
}
"""

result = gql_client.query(query, variables={"id": "123"})
print(result['user'])

WebSocket Testing

import websocket
import json
import threading

class WebSocketClient:
    def __init__(self, url):
        self.url = url
        self.ws = None
        self.messages = []
    
    def on_message(self, ws, message):
        """Handle incoming message"""
        self.messages.append({
            'timestamp': datetime.now().isoformat(),
            'data': message
        })
        print(f"Received: {message}")
    
    def on_error(self, ws, error):
        """Handle error"""
        print(f"Error: {error}")
    
    def on_close(self, ws, close_status_code, close_msg):
        """Handle connection close"""
        print(f"Connection closed: {close_status_code} - {close_msg}")
    
    def on_open(self, ws):
        """Handle connection open"""
        print("WebSocket connection opened")
    
    def connect(self):
        """Establish WebSocket connection"""
        self.ws = websocket.WebSocketApp(
            self.url,
           
           
           
           
        )
        
        ws_thread = threading.Thread(target=self.ws.run_forever)
        ws_thread.daemon = True
        ws_thread.start()
    
    def send(self, data):
        """Send message"""
        if self.ws:
            self.ws.send(json.dumps(data) if isinstance(data, dict) else data)
    
    def close(self):
        """Close connection"""
        if self.ws:
            self.ws.close()

# Usage
ws_client = WebSocketClient("wss://echo.websocket.org")
ws_client.connect()

# Send message
ws_client.send({"type": "ping", "timestamp": time.time()})

# Wait for responses
time.sleep(2)

# Close connection
ws_client.close()

Collections Management

import json
import os

class CollectionManager:
    def __init__(self, collections_dir="./collections"):
        self.collections_dir = collections_dir
        os.makedirs(collections_dir, exist_ok=True)
    
    def create_collection(self, name, requests=None):
        """Create a new collection"""
        collection = {
            'name': name,
            'created_at': datetime.now().isoformat(),
            'requests': requests or []
        }
        return collection
    
    def add_request(self, collection, request_data):
        """Add request to collection"""
        request = {
            'id': str(uuid.uuid4()),
            'name': request_data.get('name', 'Untitled'),
            'method': request_data['method'],
            'url': request_data['url'],
            'headers': request_data.get('headers', {}),
            'body': request_data.get('body', ''),
            'auth': request_data.get('auth', None),
            'params': request_data.get('params', {})
        }
        collection['requests'].append(request)
        return collection
    
    def save_collection(self, collection):
        """Save collection to file"""
        filename = f"{collection['name'].replace(' ', '_')}.json"
        filepath = os.path.join(self.collections_dir, filename)
        
        with open(filepath, 'w') as f:
            json.dump(collection, f, indent=2)
        
        return filepath
    
    def load_collection(self, name):
        """Load collection from file"""
        filename = f"{name.replace(' ', '_')}.json"
        filepath = os.path.join(self.collections_dir, filename)
        
        with open(filepath, 'r') as f:
            return json.load(f)
    
    def export_collection(self, collection, output_path):
        """Export collection to JSON"""
        with open(output_path, 'w') as f:
            json.dump(collection, f, indent=2)
    
    def import_collection(self, input_path):
        """Import collection from JSON"""
        with open(input_path, 'r') as f:
            collection = json.load(f)
        
        self.save_collection(collection)
        return collection

# Usage
manager = CollectionManager()

# Create collection
collection = manager.create_collection("User API Tests")

# Add requests
collection = manager.add_request(collection, {
    'name': 'Get All Users',
    'method': 'GET',
    'url': 'https://api.example.com/users',
    'auth': {'type': 'bearer', 'token': '${API_TOKEN}'}
})

collection = manager.add_request(collection, {
    'name': 'Create User',
    'method': 'POST',
    'url': 'https://api.example.com/users',
    'headers': {'Content-Type': 'application/json'},
    'body': json.dumps({'name': 'John Doe', 'email': 'john@example.com'}),
    'auth': {'type': 'bearer', 'token': '${API_TOKEN}'}
})

# Save collection
manager.save_collection(collection)

# Export for sharing
manager.export_collection(collection, "./exports/user_api_tests.json")

Authentication Patterns

Basic Authentication

client = APIClient(base_url="https://api.example.com")
client.set_auth("basic", {
    'username': os.getenv('API_USERNAME'),
    'password': os.getenv('API_PASSWORD')
})

response = client.request("GET", "/protected")

Bearer Token

client = APIClient(base_url="https://api.example.com")
client.set_auth("bearer", {
    'token': os.getenv('BEARER_TOKEN')
})

response = client.request("GET", "/me")

API Key (Header)

client = APIClient(base_url="https://api.example.com")
client.set_auth("api_key", {
    'key_name': 'X-API-Key',
    'key_value': os.getenv('API_KEY')
})

response = client.request("GET", "/data")

OAuth2 Flow

import requests
from urllib.parse import urlencode

class OAuth2Client:
    def __init__(self, client_id, client_secret, auth_url, token_url):
        self.client_id = client_id
        self.client_secret = client_secret
        self.auth_url = auth_url
        self.token_url = token_url
        self.access_token = None
    
    def get_authorization_url(self, redirect_uri, scope=None):
        """Generate authorization URL"""
        params = {
            'client_id': self.client_id,
            'redirect_uri': redirect_uri,
            'response_type': 'code'
        }
        if scope:
            params['scope'] = scope
        
        return f"{self.auth_url}?{urlencode(params)}"
    
    def exchange_code_for_token(self, code, redirect_uri):
        """Exchange authorization code for access token"""
        data = {
            'grant_type': 'authorization_code',
            'code': code,
            'redirect_uri': redirect_uri,
            'client_id': self.client_id,
            'client_secret': self.client_secret
        }
        
        response = requests.post(self.token_url, data=data)
        token_data = response.json()
        self.access_token = token_data['access_token']
        return token_data

# Usage
oauth = OAuth2Client(
    client_id=os.getenv('OAUTH_CLIENT_ID'),
    client_secret=os.getenv('OAUTH_CLIENT_SECRET'),
    auth_url="https://oauth.example.com/authorize",
    token_url="https://oauth.example.com/token"
)

auth_url = oauth.get_authorization_url(
    redirect_uri="http://localhost:8080/callback",
    scope="read write"
)
print(f"Visit: {auth_url}")

Request Execution Patterns

Batch Request Execution

class BatchExecutor:
    def __init__(self, client):
        self.client = client
    
    def execute_collection(self, collection, environment=None):
        """Execute all requests in a collection"""
        results = []
        env_vars = environment or {}
        
        for request in collection['requests']:
            # Replace environment variables
            url = self._replace_vars(request['url'], env_vars)
            headers = {k: self._replace_vars(v, env_vars) 
                      for k, v in request.get('headers', {}).items()}
            
            try:
                response = self.client.request(
                    request['method'],
                    url,
                    headers=headers,
                    json=json.loads(request.get('body', '{}')) if request.get('body') else None
                )
                
                results.append({
                    'request': request['name'],
                    'status': 'success',
                    'response': response
                })
            except Exception as e:
                results.append({
                    'request': request['name'],
                    'status': 'error',
                    'error': str(e)
                })
        
        return results
    
    def _replace_vars(self, text, env_vars):
        """Replace ${VAR} with environment values"""
        for key, value in env_vars.items():
            text = text.replace(f"${{{key}}}", str(value))
        return text

# Usage
executor = BatchExecutor(client)

environment = {
    'BASE_URL': 'https://api.example.com',
    'API_TOKEN': os.getenv('API_TOKEN'),
    'USER_ID': '12345'
}

results = executor.execute_collection(collection, environment)

for result in results:
    print(f"{result['request']}: {result['status']}")
    if result['status'] == 'success':
        print(f"  Status Code: {result['response']['status_code']}")

Response Validation

class ResponseValidator:
    @staticmethod
    def validate_status(response, expected_status):
        """Validate status code"""
        return response['status_code'] == expected_status
    
    @staticmethod
    def validate_json_schema(response, schema):
        """Validate JSON response against schema"""
        from jsonschema import validate, ValidationError
        
        try:
            validate(instance=response['json'], schema=schema)
            return True
        except ValidationError as e:
            return False, str(e)
    
    @staticmethod
    def validate_response_time(response, max_time_ms):
        """Validate response time"""
        return response.get('elapsed_ms', 0) <= max_time_ms

# Usage
validator = ResponseValidator()

response = client.request("GET", "/users/123")

# Validate status
assert validator.validate_status(response, 200), "Expected 200 status"

# Validate schema
schema = {
    "type": "object",
    "properties": {
        "id": {"type": "string"},
        "name": {"type": "string"},
        "email": {"type": "string", "format": "email"}
    },
    "required": ["id", "name", "email"]
}

is_valid = validator.validate_json_schema(response, schema)
assert is_valid, "Response doesn't match schema"

Configuration

Environment Variables

# .env file
API_BASE_URL=https://api.example.com
API_TOKEN=your_token_here
API_USERNAME=your_username
API_PASSWORD=your_password
OAUTH_CLIENT_ID=your_client_id
OAUTH_CLIENT_SECRET=your_client_secret
GRAPHQL_ENDPOINT=https://api.example.com/graphql
WEBSOCKET_URL=wss://api.example.com/ws

Config File

import json

class Config:
    def __init__(self, config_path="config.json"):
        self.config_path = config_path
        self.config = self.load()
    
    def load(self):
        """Load configuration"""
        try:
            with open(self.config_path, 'r') as f:
                return json.load(f)
        except FileNotFoundError:
            return self.get_defaults()
    
    def get_defaults(self):
        """Default configuration"""
        return {
            'timeout': 30,
            'retry_count': 3,
            'verify_ssl': True,
            'follow_redirects': True,
            'default_headers': {
                'User-Agent': 'API-Client-Tester/1.0'
            }
        }
    
    def save(self):
        """Save configuration"""
        with open(self.config_path, 'w') as f:
            json.dump(self.config, f, indent=2)

# Usage
config = Config()
print(f"Timeout: {config.config['timeout']}")

Troubleshooting

SSL Certificate Errors

# Disable SSL verification (not recommended for production)
response = requests.get(url, verify=False)

# Or provide custom CA bundle
response = requests.get(url, verify='/path/to/ca-bundle.crt')

Connection Timeouts

client = APIClient(base_url="https://api.example.com")

try:
    response = client.request(
        "GET", 
        "/slow-endpoint",
        timeout=10  # 10 seconds timeout
    )
except requests.exceptions.Timeout:
    print("Request timed out")

Rate Limiting

import time
from functools import wraps

def rate_limit(calls=10, period=60):
    """Rate limiting decorator"""
    timestamps = []
    
    def decorator(func):
        @wraps(func)
        def wrapper(*args, **kwargs):
            now = time.time()
            timestamps[:] = [t for t in timestamps if now - t < period]
            
            if len(timestamps) >= calls:
                sleep_time = period - (now - timestamps[0])
                time.sleep(sleep_time)
            
            timestamps.append(time.time())
            return func(*args, **kwargs)
        return wrapper
    return decorator

@rate_limit(calls=10, period=60)
def make_api_call(endpoint):
    return client.request("GET", endpoint)

WebSocket Reconnection

class ResilientWebSocketClient(WebSocketClient):
    def __init__(self, url, max_retries=5):
        super().__init__(url)
        self.max_retries = max_retries
        self.retry_count = 0
    
    def on_error(self, ws, error):
        """Handle error with reconnection"""
        print(f"Error: {error}")
        if self.retry_count < self.max_retries:
            self.retry_count += 1
            time.sleep(2 ** self.retry_count)  # Exponential backoff
            self.connect()
        else:
            print("Max retries reached")
    
    def on_open(self, ws):
        """Reset retry count on successful connection"""
        self.retry_count = 0
        print("WebSocket connection established")

Best Practices

1. Use environment variables for sensitive data (tokens, passwords)
2. Implement retry logic for transient network errors
3. Validate responses before processing data
4. Save collections for regression testing
5. Use timeouts to prevent hanging requests
6. Handle rate limits appropriately
7. Log requests and responses for debugging
8. Version your collections for tracking changes