can i implement an algorithm that fetches data on the client side

Could i implement an algorithm that fetches data and makes a nice graph of it on the client side?

15 Replies

Hi @Sven. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave: ---------------------- Yes, you can implement an algorithm that fetches data on the client side using Wasp. Wasp provides several ways to fetch data on the client side. 1. Queries: Wasp generates client-side functions that automatically take care of serialization, network calls, and cache invalidation. You can use these functions to call server code like it's a regular function. Here is an example of how to use a query in a React component:

import { getTasks, useQuery } from 'wasp/client/operations'  
  
export const MainPage = () => {  
 const { data: tasks, isLoading, error } = useQuery(getTasks)  
  
 return (  
 <div>  
 {tasks && <TasksList tasks={tasks} />}  
  
 {isLoading && 'Loading...'}  
 {error && 'Error: ' + error}  
 </div>  
 )  
}

import { getTasks, useQuery } from 'wasp/client/operations'  
  
export const MainPage = () => {  
 const { data: tasks, isLoading, error } = useQuery(getTasks)  
  
 return (  
 <div>  
 {tasks && <TasksList tasks={tasks} />}  
  
 {isLoading && 'Loading...'}  
 {error && 'Error: ' + error}  
 </div>  
 )  
}

(Source: Wasp Docs - Invoking the Query On the Frontend (https://wasp-lang.dev/docs/tutorial/queries#invoking-the-query-on-the-frontend)) 2. API Calls: You can also use the Axios wrapper from wasp/client/api to make API calls from your client. Here is an example:

import React, { useEffect } from "react";  
import { api } from "wasp/client/api";  
  
async function fetchCustomRoute() {  
 const res = await api.get("/foo/bar");  
 console.log(res.data);  
}  
  
export const Foo = () => {  
 useEffect(() => {  
 fetchCustomRoute();  
 }, []);  
  
 return <>// ...</>;  
};

import React, { useEffect } from "react";  
import { api } from "wasp/client/api";  
  
async function fetchCustomRoute() {  
 const res = await api.get("/foo/bar");  
 console.log(res.data);  
}  
  
export const Foo = () => {  
 useEffect(() => {  
 fetchCustomRoute();  
 }, []);  
  
 return <>// ...</>;  
};

(Source: Wasp Docs - Using the API from the Client (https://wasp-lang.dev/docs/advanced/apis#using-the-api-from-the-client)) 3. CRUD Operations: Wasp also generates CRUD operations that you can use in your client code. Here is an example:

import { Tasks } from 'wasp/client/crud'  
  
export const MainPage = () => {  
 const { data: tasks, isLoading, error } = Tasks.getAll.useQuery()  
  
 if (isLoading) return <div>Loading...</div>  
 if (error) return <div>Error: {error.message}</div>  
 return (  
 <div>  
 <ul>  
 {tasks.map((task) => (  
 <li key={task.id}>{task.description}</li>  
 ))}  
 </ul>  
 </div>  
 )  
}

import { Tasks } from 'wasp/client/crud'  
  
export const MainPage = () => {  
 const { data: tasks, isLoading, error } = Tasks.getAll.useQuery()  
  
 if (isLoading) return <div>Loading...</div>  
 if (error) return <div>Error: {error.message}</div>  
 return (  
 <div>  
 <ul>  
 {tasks.map((task) => (  
 <li key={task.id}>{task.description}</li>  
 ))}  
 </ul>  
 </div>  
 )  
}

(Source: Wasp Docs - Using the Generated CRUD Operations on the Client (https://wasp-lang.dev/docs/data-model/crud#using-the-generated-crud-operations-on-the-client)) Once you have fetched the data, you can use any JavaScript library to create a graph from it. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ---------------------- Sorry @Sven, I seem to be having a bit of trouble. Don't worry though, I've pinged my support and they will try to fix me up! :technologist: Perhaps try again in 15mins?

SvenOP•3mo ago

@kapa.ai But I can define an action (server side) which fetches data from a third party endpoint > stores it in db > returns the data so it can be used on the frontend. Can't i replace the part where it fetches the data from the third party endpoint to the client side, this to reduce server capacity.

kapa.ai•3mo ago

Let me check the knowledge base for you. One moment! :books: ---------------------- Yes, you can fetch data directly from a third-party endpoint on the client side, which can help reduce server load. You can use the Axios wrapper provided by Wasp to make these API calls. Here's an example:

import React, { useEffect } from "react";  
import { api } from "wasp/client/api";  
  
async function fetchThirdPartyData() {  
 const res = await api.get("<https://third-party.com/data-endpoint">);  
 console.log(res.data);  
}  
  
export const Foo = () => {  
 useEffect(() => {  
 fetchThirdPartyData();  
 }, []);  
  
 return <>// ...</>;  
};

import React, { useEffect } from "react";  
import { api } from "wasp/client/api";  
  
async function fetchThirdPartyData() {  
 const res = await api.get("<https://third-party.com/data-endpoint">);  
 console.log(res.data);  
}  
  
export const Foo = () => {  
 useEffect(() => {  
 fetchThirdPartyData();  
 }, []);  
  
 return <>// ...</>;  
};

In this example, fetchThirdPartyData is an asynchronous function that fetches data from a third-party endpoint. This function is then called inside a useEffect hook in the Foo component, so the data is fetched when the component is mounted. Please note that this approach requires the third-party server to support CORS (https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS), as the request is being made from a different origin (your client-side application). Also, be aware that any sensitive keys or credentials used to access the third-party API should not be exposed on the client side. If you need to use such keys or credentials, you should set up a server-side endpoint that handles the interaction with the third-party API, and then call this server-side endpoint from your client-side code. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ---------------------- Sorry @Sven, I seem to be having a bit of trouble. Don't worry though, I've pinged my support and they will try to fix me up! :technologist: Perhaps try again in 15mins? Let me check the knowledge base for you. One moment! :books: ---------------------- Yes, this query is safe and ensures that users can only access their own client credentials. This is achieved through the use of the context.user object and the where clause in the findFirst method. The context.user object is automatically populated by Wasp when authentication is enabled. It contains all fields of the User entity and the auth identities connected to the user. The hashedPassword field is stripped out for security reasons. If a user is not authenticated, context.user will be undefined. In your query, you first check if context.user is undefined:

if (!context.user) {
  throw new Error('User is not authenticated');
}

if (!context.user) {
  throw new Error('User is not authenticated');
}

If context.user is undefined, it means the user is not authenticated, and you throw an error. This prevents unauthenticated users from accessing any client credentials. Next, you use the findFirst method to fetch the client credentials:

const clientCredentials = await context.entities.ClientCredentials.findFirst({
  where: { userId: context.user.id },
});

const clientCredentials = await context.entities.ClientCredentials.findFirst({
  where: { userId: context.user.id },
});

In the where clause, you specify that the userId must match context.user.id. This ensures that you only fetch the client credentials for the currently authenticated user. Other users' client credentials will not be fetched because their userId will not match context.user.id. Therefore, this query ensures that users can only access their own client credentials, not the client credentials of other users. For more information on how the context.user object works, you can refer to the Wasp documentation (https://wasp-lang.dev/docs/auth/overview#using-the-contextuser-object). ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ---------------------- Sorry @Sven, I seem to be having a bit of trouble. Don't worry though, I've pinged my support and they will try to fix me up! :technologist: Perhaps try again in 15mins?

SvenOP•3mo ago

@kapa.ai can i acces context on the client side

kapa.ai•3mo ago

Let me check the knowledge base for you. One moment! :books: ---------------------- No, the context object is not directly accessible on the client side in Wasp. The context object is a server-side concept that is used in server-side functions such as actions, queries, and APIs. It contains information about the current user and the entities available in your Wasp app. On the client side, you typically interact with server-side functions (actions, queries, etc.) that use the context object. These functions are exposed to the client side as JavaScript functions that you can call. When you call these functions, Wasp automatically handles the context for you. For example, if you have a query that uses the context object:

export const getTasks = async (args, context) => {
  if (!context.user) {
    throw new HttpError(403)
  }

  const Task = context.entities.Task
  return Task.findMany()
}

export const getTasks = async (args, context) => {
  if (!context.user) {
    throw new HttpError(403)
  }

  const Task = context.entities.Task
  return Task.findMany()
}

You can call this query on the client side like this:

import { getTasks } from 'wasp/client/operations'

const tasks = await getTasks()

import { getTasks } from 'wasp/client/operations'

const tasks = await getTasks()

In this example, Wasp automatically handles the context for you when you call getTasks() on the client side. For more information, you can refer to the Wasp documentation (https://wasp-lang.dev/docs/data-model/operations/overview). ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ---------------------- Sorry @Sven, I seem to be having a bit of trouble. Don't worry though, I've pinged my support and they will try to fix me up! :technologist: Perhaps try again in 15mins?

SvenOP•3mo ago

@kapa.ai how would i send a request through client side to third part endpoint? can i use axios or is something else recommended

kapa.ai•3mo ago

Let me check the knowledge base for you. One moment! :books: ---------------------- Yes, you can use Axios to send a request from the client side to a third-party endpoint. Wasp provides an Axios wrapper that you can import from wasp/client/api. Here's an example:

import React, { useEffect } from "react";  
import { api } from "wasp/client/api";  
  
async function fetchThirdPartyData() {  
 const res = await api.get("<https://third-party.com/data-endpoint">);  
 console.log(res.data);  
}  
  
export const Foo = () => {  
 useEffect(() => {  
 fetchThirdPartyData();  
 }, []);  
  
 return <>// ...</>;  
};

import React, { useEffect } from "react";  
import { api } from "wasp/client/api";  
  
async function fetchThirdPartyData() {  
 const res = await api.get("<https://third-party.com/data-endpoint">);  
 console.log(res.data);  
}  
  
export const Foo = () => {  
 useEffect(() => {  
 fetchThirdPartyData();  
 }, []);  
  
 return <>// ...</>;  
};

SvenOP•3mo ago

@kapa.ai is they keys of the user considered sensetive? they can input their credentials from the thrid partt into the SaaS and the nthe saas retrieves data for them. They own the credentials so it wouldnt be sensetive right as only they can retrieve the credentials

kapa.ai•3mo ago

Let me check the knowledge base for you. One moment! :books: ---------------------- Yes, the keys or credentials of a user are considered sensitive information, even if they are the ones inputting it into your SaaS application. This is because these keys or credentials are typically used to authenticate the user and grant access to their data on the third-party service. If these keys or credentials were to be exposed or fall into the wrong hands, it could lead to unauthorized access and potential data breaches. Even though the users own these credentials and are inputting them into your SaaS application, it's crucial that you handle these credentials securely. This includes securely transmitting, storing, and using these credentials. You should also ensure that these credentials are not exposed in any logs, error messages, or other places where they could be inadvertently revealed. When transmitting these credentials from the client side to your server, you should ensure that the connection is secure, typically by using HTTPS. When storing these credentials, you should encrypt them to protect them in case your database is compromised. When using these credentials to interact with the third-party service, you should ensure that the connection is secure and handle any errors appropriately to avoid revealing any sensitive information. In your Wasp application, you can use the crypto-js library to encrypt and decrypt the credentials as shown in your previous code snippet. This helps to protect the credentials while they are stored in your database. Remember, even though the users are providing these credentials, it's your responsibility as the developer to handle them securely and protect your users' data. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ---------------------- Sorry @Sven, I seem to be having a bit of trouble. Don't worry though, I've pinged my support and they will try to fix me up! :technologist: Perhaps try again in 15mins?

SvenOP•3mo ago

@kapa.ai how do i prevent running an action more than once in my tsx. Now it somehtimes runs 3 times Actioncalc() this is my action.

kapa.ai•3mo ago

Let me check the knowledge base for you. One moment! :books: ---------------------- To prevent an action from running multiple times in your React component, you can use the useEffect hook. The useEffect hook allows you to perform side effects, such as calling an action, in function components. By passing an empty array ([]) as the second argument to useEffect, you can ensure that the side effect only runs once after the initial render of the component. Here's an example of how you can use useEffect to call your Actioncalc action only once:

import React, { useEffect } from 'react';
import { Actioncalc } from 'wasp/client/operations';

const MyComponent = () => {
  useEffect(() => {
    Actioncalc();
  }, []); // Empty array ensures this runs only once after initial render

  return (
    // Your component JSX here
  );
};

export default MyComponent;

import React, { useEffect } from 'react';
import { Actioncalc } from 'wasp/client/operations';

const MyComponent = () => {
  useEffect(() => {
    Actioncalc();
  }, []); // Empty array ensures this runs only once after initial render

  return (
    // Your component JSX here
  );
};

export default MyComponent;

In this example, Actioncalc is the action you want to run. The useEffect hook calls Actioncalc after the MyComponent component is initially rendered. Because the second argument to useEffect is an empty array, Actioncalc is not called again on subsequent renders. Please replace Actioncalc and 'wasp/client/operations' with the actual name of your action and the correct import path. For more information on the useEffect hook, you can refer to the React documentation (https://reactjs.org/docs/hooks-effect.html). ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ---------------------- Sorry @Sven, I seem to be having a bit of trouble. Don't worry though, I've pinged my support and they will try to fix me up! :technologist: Perhaps try again in 15mins?

SvenOP•3mo ago

@kapa.ai it still runs twice? how come that

kapa.ai•3mo ago

Let me check the knowledge base for you. One moment! :books: ---------------------- If your action is still running twice despite using useEffect with an empty dependency array, it might be due to one of the following reasons: 1. Double Rendering: In development mode, React sometimes double-renders components to help catch unexpected side effects. This is more likely if you're using React's StrictMode or if you've enabled the "Highlight updates when components render" setting in the React DevTools. However, this double rendering should not occur in production mode. 2. Parent Component Re-rendering: If the parent component of the component where you're calling the action is re-rendering, it could cause your component to unmount and remount, which would cause the action to be called again. 3. Async Action Not Handled Correctly: If Actioncalc is an asynchronous action and it's not being handled correctly, it could lead to unexpected behavior. Make sure you're properly handling promises if Actioncalc is async. Without more specific information about your code and the context in which the action is being called, it's difficult to provide a more precise answer. I would recommend checking the points above and also consider consulting the React documentation (https://reactjs.org/docs/hooks-effect.html) or relevant resources for more information. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ---------------------- Sorry @Sven, I seem to be having a bit of trouble. Don't worry though, I've pinged my support and they will try to fix me up! :technologist: Perhaps try again in 15mins?

SvenOP•3mo ago

@kapa.ai i am rendering my component in another page would that be the issue? and how would i fix this

kapa.ai•3mo ago

Let me check the knowledge base for you. One moment! :books: ---------------------- Yes, if your component is being rendered in another component (parent), and that parent component is re-rendering for some reason, it could cause your child component to unmount and remount, which would trigger the useEffect hook again and cause your action to run twice. To prevent this, you could: 1. Check if the parent component is re-rendering unnecessarily: Use React's built-in developer tools to see if the parent component is re-rendering and try to identify why. If the parent component's state or props are changing, it will cause a re-render. If you can prevent these changes, it might solve your problem. 2. Use React.memo: React.memo is a higher order component that memoizes your component. That means it will only re-render if its props have changed. This could prevent unnecessary re-renders of your child component.

import React, { memo } from 'react';

const MyComponent = memo(() => {
  // Your component code here
});

import React, { memo } from 'react';

const MyComponent = memo(() => {
  // Your component code here
});

3. Move the action to the parent component: If it makes sense in your application, you could move the action to the parent component. That way, the action would only be called when the parent component renders, not the child component. Remember, it's normal for React components to re-render often. The key is to ensure that your code can handle these re-renders without causing unwanted side effects, like calling an action multiple times. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ---------------------- Sorry @Sven, I seem to be having a bit of trouble. Don't worry though, I've pinged my support and they will try to fix me up! :technologist: Perhaps try again in 15mins?

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can i implement an algorithm that fetches data on the client side