system 2025-10-22T04:59:30Z: You are expert on react.

user 2025-10-25T04:45:35Z: createAsyncThunk for complex query logic. for example, when post user info, have to get the encrypt token first by api request

assistant 2025-10-25T04:46:40Z: Here’s how to create an async thunk with complex query logic that first fetches an encryption token and then uses it to post user data:

Basic Implementation

import { createAsyncThunk } from '@reduxjs/toolkit';

// Async thunk for posting user info with encryption token
export const postUserWithEncryption = createAsyncThunk(
  'user/postWithEncryption',
  async (userData, { rejectWithValue }) => {
    try {
      // Step 1: Get encryption token first
      const tokenResponse = await fetch('/api/auth/encryption-token', {
        method: 'GET',
        headers: {
          'Content-Type': 'application/json',
        },
      });

      if (!tokenResponse.ok) {
        throw new Error('Failed to get encryption token');
      }

      const { encryptionToken } = await tokenResponse.json();

      // Step 2: Use the token to encrypt and post user data
      const encryptedData = {
        ...userData,
        encrypted: true,
        token: encryptionToken,
        // Add your encryption logic here
        payload: await encryptData(userData, encryptionToken),
      };

      const userResponse = await fetch('/api/users', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'Authorization': `Bearer ${encryptionToken}`,
        },
        body: JSON.stringify(encryptedData),
      });

      if (!userResponse.ok) {
        throw new Error('Failed to post user data');
      }

      return await userResponse.json();
    } catch (error) {
      return rejectWithValue(error.message);
    }
  }
);

// Helper function for encryption (example)
async function encryptData(data, token) {
  // Your encryption logic here
  return btoa(JSON.stringify({ data, token, timestamp: Date.now() }));
}

Advanced Implementation with Error Handling

export const postUserWithEncryption = createAsyncThunk(
  'user/postWithEncryption',
  async (userData, { rejectWithValue, dispatch }) => {
    try {
      // Step 1: Get encryption token with retry logic
      let encryptionToken;
      let retryCount = 0;
      const maxRetries = 3;

      while (retryCount < maxRetries) {
        try {
          const tokenResponse = await fetch('/api/auth/encryption-token', {
            method: 'GET',
            headers: {
              'Content-Type': 'application/json',
            },
          });

          if (tokenResponse.ok) {
            const result = await tokenResponse.json();
            encryptionToken = result.encryptionToken;
            break;
          }
        } catch (error) {
          retryCount++;
          if (retryCount === maxRetries) {
            throw new Error('Max retries reached for token acquisition');
          }
          // Wait before retry (exponential backoff)
          await new Promise(resolve => 
            setTimeout(resolve, 1000 * Math.pow(2, retryCount))
          );
        }
      }

      if (!encryptionToken) {
        throw new Error('Could not obtain encryption token');
      }

      // Step 2: Validate token expiration
      const tokenPayload = parseJwt(encryptionToken);
      if (tokenPayload.exp * 1000 < Date.now()) {
        throw new Error('Encryption token expired');
      }

      // Step 3: Prepare encrypted payload
      const encryptedPayload = await prepareEncryptedPayload(userData, encryptionToken);

      // Step 4: Post user data
      const userResponse = await fetch('/api/users', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'X-Encryption-Token': encryptionToken,
          'X-Request-ID': generateRequestId(),
        },
        body: JSON.stringify(encryptedPayload),
      });

      if (!userResponse.ok) {
        const errorData = await userResponse.json().catch(() => ({}));
        throw new Error(errorData.message || `HTTP ${userResponse.status}`);
      }

      const result = await userResponse.json();
      
      // Step 5: Optional - Clear sensitive data from memory
      encryptionToken = null;
      
      return result;

    } catch (error) {
      console.error('Post user with encryption failed:', error);
      return rejectWithValue({
        message: error.message,
        timestamp: new Date().toISOString(),
        operation: 'postUserWithEncryption'
      });
    }
  }
);

// Helper functions
function parseJwt(token) {
  try {
    return JSON.parse(atob(token.split('.')[1]));
  } catch {
    return {};
  }
}

async function prepareEncryptedPayload(data, token) {
  // Your complex encryption/transformation logic
  return {
    encrypted: true,
    version: '1.0',
    timestamp: new Date().toISOString(),
    payload: await complexEncryption(data, token),
    metadata: {
      algorithm: 'AES-256-GCM',
      keyId: extractKeyId(token),
    }
  };
}

async function complexEncryption(data, token) {
  // Implement your actual encryption logic
  const encoder = new TextEncoder();
  const dataBuffer = encoder.encode(JSON.stringify(data));
  // ... encryption implementation
  return btoa(JSON.stringify(data));
}

function extractKeyId(token) {
  // Extract key identifier from token
  return token.split('.')[0] || 'default';
}

function generateRequestId() {
  return `req_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`;
}

Usage in Component

import React, { useState } from 'react';
import { useDispatch, useSelector } from 'react-redux';
import { postUserWithEncryption } from './userSlice';

const UserForm = () => {
  const dispatch = useDispatch();
  const { loading, error, data } = useSelector(state => state.user);
  const [formData, setFormData] = useState({});

  const handleSubmit = async (e) => {
    e.preventDefault();
    
    try {
      const result = await dispatch(postUserWithEncryption(formData)).unwrap();
      console.log('User created successfully:', result);
    } catch (error) {
      console.error('Failed to create user:', error);
    }
  };

  return (
    <form onSubmit={handleSubmit}>
      {/* Your form fields */}
      <button type="submit" disabled={loading}>
        {loading ? 'Creating...' : 'Create User'}
      </button>
      {error && <div className="error">{error.message}</div>}
    </form>
  );
};

Slice Configuration

import { createSlice } from '@reduxjs/toolkit';
import { postUserWithEncryption } from './userThunks';

const userSlice = createSlice({
  name: 'user',
  initialState: {
    loading: false,
    data: null,
    error: null,
    encryptionTokens: {},
  },
  reducers: {
    clearError: (state) => {
      state.error = null;
    },
  },
  extraReducers: (builder) => {
    builder
      .addCase(postUserWithEncryption.pending, (state) => {
        state.loading = true;
        state.error = null;
      })
      .addCase(postUserWithEncryption.fulfilled, (state, action) => {
        state.loading = false;
        state.data = action.payload;
        state.error = null;
      })
      .addCase(postUserWithEncryption.rejected, (state, action) => {
        state.loading = false;
        state.error = action.payload;
      });
  },
});

export const { clearError } = userSlice.actions;
export default userSlice.reducer;

This implementation provides:

  1. Sequential API calls - token first, then user data
  2. Error handling with proper error propagation
  3. Retry logic for token acquisition
  4. Token validation and expiration checking
  5. Security considerations for sensitive data
  6. Proper Redux state management

You can customize the encryption logic and error handling based on your specific requirements.

user 2025-10-25T04:47:30Z: How could this pattern be extended to handle more complex dependency chains where multiple sequential API calls are required before the final operation?

assistant 2025-10-25T04:49:25Z: Here are several patterns for handling complex dependency chains with sequential API calls:

1. Explicit Sequential Pattern

export const complexUserRegistration = createAsyncThunk(
  'user/complexRegistration',
  async (registrationData, { rejectWithValue }) => {
    try {
      // Step 1: Get encryption token
      const encryptionToken = await getEncryptionToken();
      
      // Step 2: Validate business rules
      const validationResult = await validateBusinessRules(registrationData);
      
      // Step 3: Check availability (depends on validation)
      const availability = await checkResourceAvailability(
        registrationData, 
        validationResult
      );
      
      // Step 4: Generate temporary storage
      const storageInfo = await createTemporaryStorage(
        registrationData, 
        encryptionToken
      );
      
      // Step 5: Final registration (depends on all previous steps)
      const user = await completeRegistration({
        ...registrationData,
        encryptionToken,
        validationId: validationResult.id,
        availabilityToken: availability.token,
        storageKey: storageInfo.key
      });
      
      // Step 6: Cleanup temporary resources
      await cleanupTemporaryResources(storageInfo.key);
      
      return user;
      
    } catch (error) {
      return rejectWithValue(error.message);
    }
  }
);

// Helper functions for each step
async function getEncryptionToken() {
  const response = await fetch('/api/auth/encryption-token');
  if (!response.ok) throw new Error('Token acquisition failed');
  const { token } = await response.json();
  return token;
}

async function validateBusinessRules(data) {
  const response = await fetch('/api/validation/business-rules', {
    method: 'POST',
    body: JSON.stringify(data)
  });
  if (!response.ok) throw new Error('Validation failed');
  return response.json();
}

async function checkResourceAvailability(data, validation) {
  const response = await fetch('/api/resources/availability', {
    method: 'POST',
    body: JSON.stringify({ data, validationId: validation.id })
  });
  if (!response.ok) throw new Error('Resource check failed');
  return response.json();
}

async function createTemporaryStorage(data, token) {
  const response = await fetch('/api/storage/temporary', {
    method: 'POST',
    headers: { 'Authorization': `Bearer ${token}` },
    body: JSON.stringify(data)
  });
  if (!response.ok) throw new Error('Storage creation failed');
  return response.json();
}

async function completeRegistration(payload) {
  const response = await fetch('/api/users/register', {
    method: 'POST',
    body: JSON.stringify(payload)
  });
  if (!response.ok) throw new Error('Registration failed');
  return response.json();
}

async function cleanupTemporaryResources(storageKey) {
  await fetch(`/api/storage/temporary/${storageKey}`, {
    method: 'DELETE'
  });
}

2. Pipeline Pattern with Dependency Injection

// Pipeline configuration
const registrationPipeline = [
  {
    name: 'encryptionToken',
    execute: async (data, context) => {
      const response = await fetch('/api/auth/encryption-token');
      return { token: (await response.json()).token };
    }
  },
  {
    name: 'validation',
    dependsOn: ['encryptionToken'],
    execute: async (data, context) => {
      const response = await fetch('/api/validation', {
        method: 'POST',
        headers: { 'X-Token': context.encryptionToken.token },
        body: JSON.stringify(data)
      });
      return await response.json();
    }
  },
  {
    name: 'availability',
    dependsOn: ['validation'],
    execute: async (data, context) => {
      const response = await fetch('/api/availability', {
        method: 'POST',
        body: JSON.stringify({
          data,
          validationId: context.validation.id
        })
      });
      return await response.json();
    }
  },
  {
    name: 'registration',
    dependsOn: ['encryptionToken', 'validation', 'availability'],
    execute: async (data, context) => {
      const response = await fetch('/api/register', {
        method: 'POST',
        body: JSON.stringify({
          ...data,
          encryptionToken: context.encryptionToken.token,
          validationContext: context.validation,
          availability: context.availability
        })
      });
      return await response.json();
    }
  }
];

export const pipelineRegistration = createAsyncThunk(
  'user/pipelineRegistration',
  async (userData, { rejectWithValue }) => {
    try {
      const context = {};
      
      for (const step of registrationPipeline) {
        // Check dependencies are available
        if (step.dependsOn) {
          const missingDeps = step.dependsOn.filter(dep => !context[dep]);
          if (missingDeps.length > 0) {
            throw new Error(`Missing dependencies: ${missingDeps.join(', ')}`);
          }
        }
        
        context[step.name] = await step.execute(userData, context);
      }
      
      return context.registration;
    } catch (error) {
      return rejectWithValue(error.message);
    }
  }
);

3. Graph-Based Dependency Resolution

class AsyncDependencyGraph {
  constructor() {
    this.nodes = new Map();
  }
  
  addNode(name, executor, dependencies = []) {
    this.nodes.set(name, { executor, dependencies });
  }
  
  async execute(initialData) {
    const results = new Map();
    const visited = new Set();
    
    const visit = async (nodeName) => {
      if (visited.has(nodeName)) return;
      visited.add(nodeName);
      
      const node = this.nodes.get(nodeName);
      if (!node) throw new Error(`Unknown node: ${nodeName}`);
      
      // Execute dependencies first
      for (const dep of node.dependencies) {
        await visit(dep);
      }
      
      // Execute current node
      const dependencyResults = {};
      for (const dep of node.dependencies) {
        dependencyResults[dep] = results.get(dep);
      }
      
      const result = await node.executor(initialData, dependencyResults);
      results.set(nodeName, result);
    };
    
    // Execute all nodes
    for (const nodeName of this.nodes.keys()) {
      await visit(nodeName);
    }
    
    return Object.fromEntries(results);
  }
}

// Configure the dependency graph
const registrationGraph = new AsyncDependencyGraph();

registrationGraph.addNode('encryptionToken', async (data) => {
  const response = await fetch('/api/auth/encryption-token');
  return (await response.json()).token;
});

registrationGraph.addNode('validation', async (data, deps) => {
  const response = await fetch('/api/validation', {
    headers: { 'X-Token': deps.encryptionToken },
    body: JSON.stringify(data)
  });
  return response.json();
}, ['encryptionToken']);

registrationGraph.addNode('availability', async (data, deps) => {
  const response = await fetch('/api/availability', {
    body: JSON.stringify({
      data,
      validationId: deps.validation.id
    })
  });
  return response.json();
}, ['validation']);

registrationGraph.addNode('registration', async (data, deps) => {
  const response = await fetch('/api/register', {
    method: 'POST',
    body: JSON.stringify({
      ...data,
      encryptionToken: deps.encryptionToken,
      validationContext: deps.validation,
      availability: deps.availability
    })
  });
  return response.json();
}, ['encryptionToken', 'validation', 'availability']);

export const graphBasedRegistration = createAsyncThunk(
  'user/graphRegistration',
  async (userData, { rejectWithValue }) => {
    try {
      const results = await registrationGraph.execute(userData);
      return results.registration;
    } catch (error) {
      return rejectWithValue(error.message);
    }
  }
);

4. State Machine Pattern with Progress Tracking

const RegistrationStates = {
  INIT: 'init',
  GETTING_TOKEN: 'getting_token',
  VALIDATING: 'validating',
  CHECKING_AVAILABILITY: 'checking_availability',
  CREATING_STORAGE: 'creating_storage',
  REGISTERING: 'registering',
  CLEANING_UP: 'cleaning_up',
  COMPLETED: 'completed',
  FAILED: 'failed'
};

export const stateMachineRegistration = createAsyncThunk(
  'user/stateMachineRegistration',
  async (userData, { rejectWithValue, dispatch }) => {
    let currentState = RegistrationStates.INIT;
    const context = {};
    
    const updateProgress = (state, data = null) => {
      currentState = state;
      dispatch(updateRegistrationProgress({ state, data }));
    };
    
    try {
      updateProgress(RegistrationStates.GETTING_TOKEN);
      context.encryptionToken = await getEncryptionToken();
      
      updateProgress(RegistrationStates.VALIDATING);
      context.validation = await validateBusinessRules(userData);
      
      updateProgress(RegistrationStates.CHECKING_AVAILABILITY);
      context.availability = await checkResourceAvailability(userData, context.validation);
      
      updateProgress(RegistrationStates.CREATING_STORAGE);
      context.storage = await createTemporaryStorage(userData, context.encryptionToken);
      
      updateProgress(RegistrationStates.REGISTERING);
      const result = await completeRegistration({
        ...userData,
        ...context
      });
      
      updateProgress(RegistrationStates.CLEANING_UP);
      await cleanupTemporaryResources(context.storage.key);
      
      updateProgress(RegistrationStates.COMPLETED, result);
      return result;
      
    } catch (error) {
      updateProgress(RegistrationStates.FAILED, { error: error.message });
      
      // Attempt cleanup on failure
      if (context.storage) {
        await cleanupTemporaryResources(context.storage.key).catch(() => {});
      }
      
      return rejectWithValue(error.message);
    }
  }
);

// Progress tracking slice
const registrationSlice = createSlice({
  name: 'registration',
  initialState: {
    currentState: RegistrationStates.INIT,
    progress: 0,
    stepData: null,
    error: null
  },
  reducers: {
    updateRegistrationProgress: (state, action) => {
      state.currentState = action.payload.state;
      state.stepData = action.payload.data;
      state.progress = calculateProgress(action.payload.state);
      if (action.payload.state === RegistrationStates.FAILED) {
        state.error = action.payload.data?.error;
      }
    }
  }
});

function calculateProgress(state) {
  const states = Object.values(RegistrationStates);
  const currentIndex = states.indexOf(state);
  return (currentIndex / (states.length - 1)) * 100;
}

5. Composable Steps with Error Recovery

class ComposableWorkflow {
  constructor() {
    this.steps = [];
    this.rollbackActions = [];
  }
  
  addStep(name, execute, rollback = null, dependencies = []) {
    this.steps.push({ name, execute, rollback, dependencies });
  }
  
  async execute(initialData) {
    const context = {};
    
    for (let i = 0; i < this.steps.length; i++) {
      const step = this.steps[i];
      
      try {
        // Verify dependencies
        const missingDeps = step.dependencies.filter(dep => 
          !context[dep]
        );
        if (missingDeps.length > 0) {
          throw new Error(`Missing dependencies: ${missingDeps.join(', ')}`);
        }
        
        // Execute step
        const dependencyContext = {};
        step.dependencies.forEach(dep => {
          dependencyContext[dep] = context[dep];
        });
        
        context[step.name] = await step.execute(initialData, dependencyContext);
        
        // Register rollback if provided
        if (step.rollback) {
          this.rollbackActions.unshift({
            name: step.name,
            execute: step.rollback,
            context: { ...dependencyContext, [step.name]: context[step.name] }
          });
        }
        
      } catch (error) {
        console.error(`Step ${step.name} failed:`, error);
        
        // Execute rollback for completed steps
        await this.rollback();
        throw error;
      }
    }
    
    return context;
  }
  
  async rollback() {
    for (const action of this.rollbackActions) {
      try {
        await action.execute(action.context);
      } catch (rollbackError) {
        console.error(`Rollback failed for ${action.name}:`, rollbackError);
      }
    }
  }
}

// Usage
const workflow = new ComposableWorkflow();

workflow.addStep(
  'encryptionToken',
  async (data) => {
    const response = await fetch('/api/auth/encryption-token');
    return (await response.json()).token;
  }
);

workflow.addStep(
  'temporaryStorage',
  async (data, deps) => {
    const response = await fetch('/api/storage/temporary', {
      headers: { 'Authorization': `Bearer ${deps.encryptionToken}` },
      body: JSON.stringify(data)
    });
    return response.json();
  },
  async (context) => {
    // Rollback: delete temporary storage
    await fetch(`/api/storage/temporary/${context.temporaryStorage.key}`, {
      method: 'DELETE'
    });
  },
  ['encryptionToken']
);

// Export thunk using composable workflow
export const workflowRegistration = createAsyncThunk(
  'user/workflowRegistration',
  async (userData, { rejectWithValue }) => {
    try {
      const results = await workflow.execute(userData);
      return results.finalStep; // Return the final result
    } catch (error) {
      return rejectWithValue(error.message);
    }
  }
);

Key Benefits of These Patterns:

  1. Explicit Dependencies - Clear declaration of what depends on what
  2. Error Isolation - Failures in one step don’t break the entire flow
  3. Progress Tracking - Monitor each step’s completion
  4. Rollback Capability - Clean up resources on failure
  5. Testability - Each step can be tested independently
  6. Reusability - Steps can be reused across different workflows
  7. Maintainability - Clear separation of concerns

Choose the pattern that best fits your complexity requirements and team preferences. The Pipeline Pattern is great for linear flows, while the Graph-Based approach handles complex dependencies well.