Ooblog722

Installing Node.js via package manager. Note: The packages on this page are maintained and supported by their respective packagers, not the Node.js core team. Please report any issues you encounter to the package maintainer. If it turns out your issue is a bug in Node.js itself. Curl is a way you can hit a URL from your code to get an HTML response from it. In NodeJS/ExpressJS we use “request” module for this purpose. In Simple Words, if we want to access HTML content of any site we pass that URL to request and it returns the HTML source code. Although there are no specific NodeJS bindings for cURL, we can still issue cURL requests via the command line interface. NodeJS comes with the childprocess module which easily allows us to start processes and read their output. Doing so is fairly straight forward. We just need to import the exec method from the childprocess module and call it. If you’ve already got a multi-node swarm running, keep in mind that all docker stack and docker service commands must be run from a manager node. A current version of Docker Compose. Set up a Docker registry. Because a swarm consists of multiple Docker Engines, a registry is required to distribute images to all of them.

1. Node Curlers
2. Node Curly

Seraphine twitter. Estimated reading time: 7 minutes

Node-request-to-curl Adds a.toCurl method to http.ClientRequests to generate output equivalent to the 'Copy as Curl' option in the WebKit debugger.

When running Docker Engine in swarm mode, you can use docker stack deploy todeploy a complete application stack to the swarm. The deploy command acceptsa stack description in the form of a Compose file.

The docker stack deploy command supports any Compose file of version “3.0” orabove. If you have an older version, see the upgrade guide.

To run through this tutorial, you need:

1. A Docker Engine running in swarm mode.If you’re not familiar with swarm mode, you might want to readSwarm mode key conceptsand How services work.

   Note

   If you’re trying things out on a local development environment,you can put your engine into swarm mode with docker swarm init.

   If you’ve already got a multi-node swarm running, keep in mind that alldocker stack and docker service commands must be run from a managernode.

2. A current version of Docker Compose.

Set up a Docker registry

Because a swarm consists of multiple Docker Engines, a registry is required todistribute images to all of them. You can use theDocker Hub or maintain your own. Here’s how to createa throwaway registry, which you can discard afterward.

1. Start the registry as a service on your swarm:

2. Check its status with docker service ls:

   Once it reads 1/1 under REPLICAS, it’s running. If it reads 0/1, it’sprobably still pulling the image.

3. Check that it’s working with curl:

Create the example application

The app used in this guide is based on the hit counter app in theGet started with Docker Compose guide. It consistsof a Python app which maintains a counter in a Redis instance and increments thecounter whenever you visit it.

1. Create a directory for the project:

2. Create a file called app.py in the project directory and paste this in:

3. Create a file called requirements.txt and paste these two lines in:

4. Create a file called Dockerfile and paste this in:

5. Create a file called docker-compose.yml and paste this in:

   The image for the web app is built using the Dockerfile definedabove. It’s also tagged with 127.0.0.1:5000 - the address of the registrycreated earlier. This is important when distributing the app to theswarm.

Test the app with Compose

1. Start the app with docker-compose up. This builds the web app image,pulls the Redis image if you don’t already have it, and creates twocontainers.

   You see a warning about the Engine being in swarm mode. This is becauseCompose doesn’t take advantage of swarm mode, and deploys everything to asingle node. You can safely ignore this.

2. Check that the app is running with docker-compose ps:

   You can test the app with curl:

3. Bring the app down:

Push the generated image to the registry

To distribute the web app’s image across the swarm, it needs to be pushed to theregistry you set up earlier. With Compose, this is very simple:

The stack is now ready to be deployed.

Deploy the stack to the swarm

1. Create the stack with docker stack deploy:

   The last argument is a name for the stack. Each network, volume and servicename is prefixed with the stack name.

2. Check that it’s running with docker stack services stackdemo:

   Once it’s running, you should see 1/1 under REPLICAS for both services.This might take some time if you have a multi-node swarm, as images need tobe pulled.

   As before, you can test the app with curl:

   Thanks to Docker’s built-in routing mesh, you can access any node in theswarm on port 8000 and get routed to the app:

3. Bring the stack down with docker stack rm:

4. Bring the registry down with docker service rm:

5. If you’re just testing things out on a local machine and want to bring yourDocker Engine out of swarm mode, use docker swarm leave:

Node Curlers

Problem

Node Curly

I'm going to test via Curl a simple application with Nodejs.

curl command is:

and Node.js runs like:

and somewhere else in users:

output is {}. req.body, instead, is undefined.

How can I retrieve that parameters with curl? Am I missing something?

Related Articles

Solution

To read POST data with Express, you will have to use app.use(express.bodyParser());.

Quoting here:

This property is an object containing the parsed request body. This feature is provided by the bodyParser() middleware, though other body parsing middleware may follow this convention as well. This property defaults to {} when bodyParser() is used.

Although it says Express defaults to {} when bodyParser() is used, I think that's a typographical error and is the opposite.

Discussion

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