I'm new to cloud foundry, so I'm not sure, if my thoughts and plans are right. Maybe someone can explain or discuss it with me.
What I want to do:
Implement a MTA (Multitarget Application) with a a html5-module as frontend and a nodeJS-module as backend. Furthermore there should be a mongodb instance, which will be accessed from the nodejs-module. Later it should also get multitenant.
What I already did:
I implemented a simple nodejs-app and connected it to the db. Persisting and calling data with rest works already fine. I implemented a simple sapui5 app, which consumes data from the db with ajax. For now, the node startscript is in the html5 module, so it works somehow. But now I want to separate the modules.
So I created a mta-project with the two modules in webide and imported the two apps.
What I expect to do for it:
For now, I have an approuter, which is in my nodejs-module, but I can not access the webapp folder in the html5-module from here: file not found error: /home/vcap/app//. Is there a possibility to access the webapp-folder in another module over the path "/home/vcap/app/"? Or can I lookup the app-directory anywhere?
I have read, that an approuter-module (nodejs) can be needed, but I don't know exactly what it does. I think it serves the index.html file when opening the url of the whole app?
Related
I am developing my own website. So far, I've used React for the frontend and Flask for the backend. I've been doing frontend development for a while now but I'm just starting to get into the backend.
From my limited understanding, frameworks like Flask and ExpressJS create their own servers and host data that the frontend can use. It seems to me that that they automatically create websites to host and receive data. In my website, I route the backend to do what I want and use fetch requests with POST and GET from the frontend to communicate.
Although it works, to me, it seems overly complex. Why does the backend need it's own server? It seems unnecessary to create a proxy for the frontend and fetch data. Why can a website not just run custom code in the background, why does it need a service like Flask or ExpressJS to run in the background for it? These backend frameworks run Python or NodeJS in the background, but wouldn't it be much simpler if the website itself could run Python or NodeJS in the background?
I also see that in frameworks like React, you can import things and use modules— like in NodeJS. While importing some modules works, the require keyword is not allowed and normal NodeJS code will not work. Therefore, the backend will not work. Why is this— why can't you just run backend code natively? Instead you have to go through fetch and specify headers to basically translate information from your frontend to your backend.
Forgive my amateur understanding of web development, but the frontend/backend system seems overly complex to me. Thanks in advance.
Why does the backend need it's own server?
Where will the client store data so that when you open the page again the data will still be there? You can use localStorage but this is locked to that particular browser. What if someone logs in on a different device or uses a different browser?
Where will the client get the application from in the first place? Your application needs to be packaged up in a form that can be easily downloaded, and it needs an address to be loaded from. This is all considered "back end" even if you're using a static hosting service like GitHub Pages.
There's a lot of reasons why a back-end exists and needs its own server. Any application with persistent state which is expected to work across different sessions needs at least one of these.
I have a NodeJS file that processes IoT data. It runs on a domain, and I have a different DOCROOT for this domain, point to /public.
Ideally I would store my main.js file outside the public folder so the javascript source code remains protected. But how would a user be able to interact with the server? Would that be to create a public/main.js, that includes the main.js file from the public parents folder. Is this correct?
So my guess is that the folder structure would be like this:
/node_modules
/public
/public/main.js
/.env
/.gitignore
/main.js
/package-lock.json
/package.json
/README.md
Is this how one would safely deploy a NodeJS server script? Or should it be done differently? I'm sorry if this is an inappropriate question, but I'm new to NodeJS and would appreciate some guidance.
Nodejs is usually server-sided and not client-sided, meaning you would need a server/host to run the code (just like you need to run "node main.js"). There are many options out there, but as an example you could use heroku.com.
When the scripts are deployed on a server/hosting platform, the users are not able to read the source files (as long as you don't make them available within the code).
In order for the users to be able to interact with the data/server you would need to create a endpoint that allows the users to connect to the server. You could for example use the npm library called "express". This would allow you to create different endpoints on the server that the users can access.
Not sure how much this helped or if I understood this correctly, but let me know :)
I am new to Node and web development. I am working on a simple application to get started and want to limit the use of my endpoints to server side calls, i.e. anyone else trying to access them gets a 403.
However, after researching, I found PassportJS with examples of how to protect endpoints, but they all seem to be overkill especially for a small application like mine.
Am I overthinking this, or should I be looking for a more basic solution?
How do you need to consume these end points yourself? I don't know if all you are looking to do is to call one file from the other. You need not expose them as restful end points in that case. Create the methods as module methods (as in node modules). Then just use require syntax to reference that file as a dependency.
You need restful end points for server side only if it needs to be called from another web application.
I'm migrating a combined Azure Website (with both Controllers and ApiControllers) to a split Web App and API App. Let's call it MyApp.
I've created MyAppDevApi, MyAppTestApi, and MyAppProductionApi API Apps (in different App Services) to host the three environments, expecting to promote code from one environment to another.
So far, I've only deployed to MyAppDevApi, since I'm just getting started.
When I do Add/Azure API App Client to my UI-only project to start referring to the API app, and I point it to MyAppDevApi, it uses AutoRest to create classes in my code. These classes now all have the name MyAppDevApi, rather than just MyAppApi, which is the actual namespace of the code I'm deploying to every environment. Obviously, I can't check that in... how can I promote that through Test and Prod?
There's nothing in the Swagger JSON that refers to this name, so it must be on the AutoRest side (I think).
Has anyone come up with a strategy or work-around to deal with this multiple-environment promotion issue with API Apps?
Edit
So far the best thing I've come up with is to download the Swagger from the API App to a local file (which, again, has only the namespace from the original code, not from the name of the API App), and then import it into the Web App. This will generate classes in the Web App that have the naming I expect.
The problem is that I then have to edit the generated MyAppApi.cs file's _baseUri property to pull from an AppSetting, have the different web.config.dev, .test, .prod, and then do the web.config transform. I mean, that'll work, but then every time I change the API App's interface, I'll regenerate... and then I'll have remember to change the _baseUri again... and someone, sometime is going to forget to do this and then deploy to production. It's really, really fragile.
So... anyone have a better idea?
I'm not quite sure why you're creating three different apps, one for each environment? One application is fine and use web.config transforms for each environment. This is the general way I do all of my apps and works fine.
Information about how to apply web.config transforms can be found here which may help in your situation.
Hope that helps.
Well, here's how I've solved this:
Download Swagger file from API App to local hard drive.
Import local Swagger file into Web App to generate classes that have the naming from my code, not from the environment.
Use AppSettings to specify the environment-specific settings to point to the API App. This can be either a web.config transform, or you can just specify them in the Azure Portal on the Web App in Application Settings.
Instantiate the generated API App Client using the constructor that takes in a URL to point to the API App (these are at class level, hence static):
private readonly static Uri apiAppUrl = new Uri(CloudConfigurationManager.GetSetting("ApiAppUrl"));
private readonly static MyAppApi myAppApi = new MyAppApi(apiAppUrl);
I'd still love a solution to this that doesn't require downloading the Swagger file, but, all in all, if that's the only workaround necessary, it's not all that bad.
I developed a small node.js app in which I can configure conditions for a custom javascript file, which can be embedded in a webpage, and which modifies the DOM of that page in the browser on load. The configuration values are stored in MongoDB. (For sake of argument: add class "A" to DOM element with ID "B" )
I have difficulties to figure out the best way to serve requests / the JavaScript file.
Option 1 and my current implementation is:
I save a configuration in the node app and a distinct JavaScript
file is created for that configuration.
The page references that file which is hosted and served by the server.
Option 2 and where I think I want and should go is:
I saves a configuration (mongodb) NO JavaScript file is created Pages
a generic JavaScript link (for instance: api.service.com/javascript.js)
Node.js / Express app processes the request, and
returns a custom JavaScript (file?) with the correct values as saved in mongodb for that configuration
Now, while I believe this is the right way to go about it, I am unsure HOW to go about it. Any ideas and advise are very welcome!
Ps: For instance I wonder how best to authenticate or identify the origin, user and requested configuration. Shall I do this like: api.service.com/javascript.js&id="userID" - is that good practice?
Why not serve up a generic Javascript file which can take a customized json object (directly from mongodb) and apply the necessary actions? You can include the json data on the page if you really need to have everything embedded, but breaking up configuration and code is the most maintainable approach.