Almost every web and mobile application retrieve the data when a user makes a request. Web applications get the data from the database when a user makes request. Most of us every day publish new pictures of our family members, colleagues, and friends on facebook. You must remember when you click on the post button on facebook, and it publishes your data very quickly.
Web services are working behind an app to process the request made by a user. Now, here Axios comes into the light. Axios is a well-known package, and it has got around 63, stars on GitHub and forked nearly times at the time of creating this tutorial. This app will have users, and users can be created, retrieved, updated, and deleted from the MongoDB database using Axios. Check out your React project on this URL: localhost Inside this folder create the following components.
Then, connect the routers with respective components. Here, we will create a user form using Bootstrap 4 UI component. Create a separate folder inside the root of the React app and name it serverhere we will keep all the server related files. Install nodemon NPM package as development dependency to automate the server re-starting process. Create a new folder by the name of database inside the server folder, and also create a file by the name of db.
We will declare the database in server. Declare Mongoose Schema Now, create another new folder by the name of models inside the server node backend folder. And also create a file by the name of user-schema. In this step, we will create a separate folder inside the server folder by the name of routes and also create a file by the name of user.React Image Upload Made Easy
We can show this data in our React app. Add the following code inside of this file. We barely scratched the surface in this tutorial, and there are more things which you can do with Axios in regards to make the HTTP calls. I hope you loved this article.Python is a dynamic language widely adopted by companies and developers.
Check the version of Python installed by running the following command:. Python has a powerful tool to manage dependencies called pipenv. To install pipenv on your machine follow these steps:. With pipenv installed, create a directory for your backend code:. The command above will create a Python 3 virtual environment. Now you can install Flask by running the following command:.
To import them run the following commands:. By end of this section your back-end application will be capable to handle the following HTTP calls:. GithubRepoSchema will represent a Github repository sent by the clients whereas KudoSchema will represent the data you are going to persist in the database. The above commands will create the app directory with another directory within it called kudo then, the second command will create three files: schema.
Copy and paste the content below within the schema. Install the marshmallow library running the following commands:. You have now your first files in place.
Using Axios with React
The schemas were created to represent the incoming request data as well as the data your application persists in the MongoDB. In order to connect and to execute queries against the database, you are going to use a library created and maintained by MongoDB itself called pymongo. Install the pymongo library running the following commands:.
This tutorial assumes you have Docker and docker-compose installed. With MongoDB up and running you are ready to work the MongoRepository class, it is always a good idea to have class with just a single responsibility, so the only point in your back-end application MongoDB is going to be explicitly dealt with is in the MongoRepository.
Start by creating a directory where all persistence related files should sit, a suggestion would be: repository. Notice that all methods explicitly use the pymongo API.
To export the environment variable, run:. Since you might want to use other database in the future, it is a good idea to decouple your application from MongoDB. For the sake of simplicity you are going to create an abstract class to represent a Repositorythis class should be the one used throughout your application. Within this directory, you will have two files, endpoints. To create them run the following commands:.
To install it run the following command:. Now that you understand the role of the JWT middleware, you need to write it. Paste the following content to the middlewares. Flask provide a module called g which is a global context shared across the request life cycle.
Next, implement your endpoints. Installing create-react-app is simple. In this tutorial you will use yarn.Not only that, but works great with React and many other frameworks. Axios provides support for request and response interceptors, transformers and auto-conversion to JSON. The process is very straightforward. By default, our project is pretty empty. The code inside API. Finally, you can create a new file User. The User component will serve as our user placeholder card.
The User component is a simple component that displays a user avatar, his or her name and email inside a card. It accepts an isLoading boolean prop, which if is set to true it will display a Loading Otherwise, it will display the actual user details.
Ok, we have a component, but where should we make the actual request to our API to load the data? The answer is inside the componentDidMount lifecycle hook. If you need to load data from a remote endpoint, componentDidMount is a good place to make requests. Now the App. We also created the async componentDidMount method.
That will trigger a new re-render. Notice that the method is async which will allow us to await certain actions inside. When the action completes, we store the data inside the userData variable. Next, we update the variable with the returned data for ease of use. Finally, we create easy to use variables name, avatar, email and update the state with their values.
I have a react form in frontend where users can submit a question they wanna ask. Send the form data to flask server, using some NLP models to compute and get a result. Then return the result to the frontend. The problem is: I can see the data posted to flask server, but getting null when I try to GET results from flask server. The flask endpoint It is just a test model and I am trying to return the question itself right now :.
You're not getting server response because of CORS policy. In short, browsers do not, by default, let ajax requests to be made to any address which has different port, protocol or domain than your page, unless the server allows it, by adding a certain response header. In your case means your react app can't communicate with flask server running on a different port, but you can make some changes to flask configuration for allowing cross-origin requests.
There are some packages available for this, e. Learn more. Asked 4 months ago. Active 4 months ago. Viewed 72 times. Here is the handleSubmit method in QuestionForm. Rui Rui 23 5 5 bronze badges. Check the logs on your API. You may need additional configuration with CORS: see both the answers to stackoverflow.
Active Oldest Votes. Pranav Gupta Pranav Gupta 6 6 silver badges 11 11 bronze badges. What do you get in console after that? I think the frontend is trying to get the results before posting the data, that's why I'm getting null, but I still don't know how to fix it.
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Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog.We are also going to style the user interface of our app with Bootstrap 4 components such as the Container and Card components. React is a popular user interface library created by Facebook. It's declarative, component-based and can be used to build both web and mobile applications using web technologies.
If you have Node and NPM installed, go ahead and open a new terminal, next run the following command to install the tool globally in your system:.
Note : Please note that depending on your npm configuration you may be required use sudo in your command in Linux and macOS for installing npm packages system-wide.
Deploying a Flask and React Microservice to AWS ECS
Now that you have installed create-react-applet's proceed to create our React project. Go back to your terminal window and run the following commands:. We first navigate to our working directory and use the npx create-react-app command to create our React project. See more details from the official website.
The tool will create a basic project structure and install the required dependencies from npm. After that, you can simply navigate to your project's root folder and serve your React application using the npm start script:. For building a beautiful UI we'll be using Bootstrap 4. Fortunately for us, using Bootstrap 4 with React is dead easy. Now, let's test if Bootstrap is successfully integrated. Now let's install Axios in our React project using the following command from your project's root folder:.
We use the axios. If you open your browser console, you should see the received users displayed as an array of objects. Now, let's render the users array in our React app. In our render method, we simply go through the state. We can also embed any expressions in JSX by wrapping them using curly braces. As a recap:. We have started by installing the create-react-app tool then used it to create our React project.
If you are new to React; you will also learn about the basic concepts such as: The state object which is used to contain the pieces of state of the app and the setState method to change the values in the state object.
Flask: This a micro web framework written in python. You can find the full implementation and code used in this article on this GitHub repository. To unpack webpack, make sure you are in the react-app directory and run this command; npm run eject. What this does is that it gives us access to the config files.
It unpacks webpack. After unpacking webpack, you will notice a new folder created under react-app called config. We can now go ahead and edit our paths. This can be achieved by changing our appbuild entry to the actual path where we want our files to go. Replace the appbuild entry with this line of code below. As you recall above, we created the static folder under the flask-server folder to contain the react application build.
Hence, after a complete build of the react application, you will notice that all the files will be in the react folder that will be created. Open webpack. What we want to do is to get rid of all of them.
You can do this manually or use your editor to search for all of them and delete them at once. The next thing we need to do is to tell webpack where to put our HTML files. Got to the HtmlWebpackPlugin and add a file name to your config, as shown below. Open index. After the title tag, add a script tag shown below.
It is then accessible anywhere in our react app under window. Go to package. Change your Command-line directory to flask-server and run python3 main.
If you have been building your application following this tutorial, compare it with the image below. NB: There is a drawback of losing the hot reload offered by the built-in debug server of NPM; hence, every time you make changes to the react app, you need to build it again with npm run build command to see the changes in your app.
As a Python developer, I got curious about how I could serve a react app created by create-react- app with a flask server. And with this curiosity, I was able to achieve this. Check out this link for a detailed approach. I hope you have learned something new from this article. Feel free to leave any comment or suggestion in the comment section below. This will help all readers of your article to have a fully functional application with enough knowledge about how to serve a React App with a flask server thus enabling them to develop as many feature as they can in other different applications.
This was great. I followed the instructions and managed to get React served through Flask. I then deployed the Flask server to Heroku, which involved a little tweaking of the file locations.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Have a question about this project?
Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub? Sign in to your account. As seen above, I have added the relevant header, but it does not solve the issue.
I made the same request from my terminal using cURL and it worked fine. When you mention that you added the relevant header, I assume you mean you added those headers to the request.
Actually, the header is expected in the response headers from the server, indicating that the resource is allowed to be accessed by other websites directly. Since your API does not support it, you have two options. I have searched through various forums and questions on Stack Overflow and I can't seem to find any solution to this. It would be appreciated if someone could provide some insight. The difference is in a and boards. PetitBateau I'm not sure how the Chrome extension would help sending requests through axios.
A Chrome extension helps only for those who have the extension. Depending on Chrome extension in production is not a good idea, as not everyone has that extension.
One thing you could do if you have access to your website server-side codebase, is to create a controller action there assuming you are using an MVC and then use it to consume the remote service. You can then make AJAX requests to your controller action. A bonus to this approach is that you could run additional checks before contacting the remote service, formatting its response and even caching it. Read this, everyone. My solution is to create my own api on my domain server to access any foreign api that doesnt allow cross-origin requests, I call it my repeater api.
Normally this would work, but in the case that it doesn't and you don't have any access to that domain The server needs to respond with CORS headers on the options call. I have long solved that problem though. The server belongs to a 3p service and therefore out of my control. I simply proxied it instead. All is well on that front. I totally confuse how to handle this error.
Why is there no official solution to this problem? I read through this whole thread and am baffled at what seems like a universal problem that no one is really solving in any standard way. It's a security feature built into most or all browsers. There are ways to 'hack' around it, but it's up to the server to respond with the correct headers.
So given that response, what's the most "successful" way of implementing a fix for a CORS issue then? Speaking strictly, this is not an axios issue. Actually this must not even be considered an issue. In the example with the 4chan api, as was said before, the problem is not axios, is the 4chan api itself who is not following the CORS standards. Some people has suggested the old trick of use a proxy to handle7avoid all that headers validations.
In my case I was two days trying to connect to a asp net core api in my own localhost until I realize axios, before sending my get request, automatically was sending a "preflight requests" who is sendign as a OPTIONS method which my server was not prepared to handle.
If there is someone who blame is to chrome and firefox for display a message so ambiguous.