Category Archives: react check if url exists

React check if url exists

GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. If nothing happens, download GitHub Desktop and try again.

If nothing happens, download Xcode and try again. If nothing happens, download the GitHub extension for Visual Studio and try again.

This package is greatly inspired by jayesbe 's amazing react-native-cacheable-image but adds some functionality that we were missing when trying to handle caching images in our react-native app. We use react-native-fetch-blob to handle file system access in this package and it requires an extra step during the installation. This is where all the cache magic takes place. If the URL exists in cache and is not expired, resolve with the local cached file path.

Otherwise, download the file to the cache folder, add it to the cache and then return the cached file path. Otherwise, copy the seed file into the cache folder, add it to the cache and then return the cached file path. CachedImage is a drop in replacement for the Image component that will attempt to cache remote URLs for better performance. It's main use is to hide the cache layer from the user and provide a simple way to cache images. CachedImage uses an instance of ImageCacheManager to interact with the cache, if there is an instance provided by ImageCacheProvider via the context it will be used, otherwise a new instance will be created with the options from the component's props.

A set of options that are provided to the ImageCacheManager and provide ways to customize it to your needs.

Skip to content. Dismiss Join GitHub today GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Sign up. CachedImage component for react-native.

JavaScript Branch: master. Find file. Sign in Sign up. Go back. Launching Xcode If nothing happens, download Xcode and try again. Latest commit. Kfir Golan v1. Latest commit dea Oct 24, Installation npm install react-native-cached-image --save - or - yarn add react-native-cached-image We use react-native-fetch-blob to handle file system access in this package and it requires an extra step during the installation.

You should only have to do this once. You signed in with another tab or window. Reload to refresh your session.By using this site, you agree to our updated Privacy Policy and our Terms of Use.

Manage your Cookies Settings. Join Now login. Ask Question. My question is: How can I prevent form submission when MyUrl. Aug 24 ' Post Reply. Share this Question. Matt Kruse. Why would a form target url not be available?

Why write the target url to begin with, then? Or is this completely dynamic?

react check if url exists

I would say don't just prevent the form from submitting if the target doesn't exist. Don't even draw the form. Why waste time fillingit out if it can't be submitted?

Anyway, to answer your question there are a few possibilities. One would be to use ajax to "GET" the url and see if the server comes back with a error.

If not, then submit. Thanks Matt for helping. It's not a "real" user form. It's only a device to pass some information from a web page to a server via an asp page in a dynamic context. You are recommending something I am not familiar with at all. I do not know whether I am able to embark in that The Netherlands. Please change the x'es to dots in my emailaddress. Hi Evertjan this would be ingenius I have tried this with various url included itself "Default.

Another problem is that this displays at each reload. Is it possible to transform that in a function returning a boolean variable so that it can be used to allow or forbid Submit?

Thank for the help, Pam Evertjan. Laurent Bugnion. I still have an error in Firefox, not sure what it is, and it's too late now to look for it.

Sorry about that. If you try to access other domains, you'll need to relax security on the web client. Thanks Laurent, that's very nice. Ok I am willing to use it.

How to Get URL Parameters with Javascript

But keep in mind I know nothing about this "Ajax" technology actually I am studying some javascript by a couple of days. I would need some step by step indication of what I have to do. After that I should be able to begin move the first steps in this new fashinating world. Thanksvery much for the help.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. It only takes a minute to sign up.

I have a custom page to upload file to document library. For example, if there are 10 person, so inside root folder, I have 10 folder for each person, Named as per the ID of the person.

So while uploading, there is a textbox where I enter the ID of that person. Now when I click on upload button, I need to check if the folder for that person exist in root folder. If it exist, I need to upload it there. By the code above, i get all the root folders, Now I need to check if a folder named test exist in any of those folders. So I wanted to ask if there is any lambda expression kind of code that I can write to search this test folder in all those folders.

You can specify the full path to get the folder, i. Sign up to join this community. The best answers are voted up and rise to the top.

Home Questions Tags Users Unanswered. Asked 2 years, 11 months ago. Active 1 year, 9 months ago. Viewed 5k times. KumarV KumarV 2, 5 5 gold badges 35 35 silver badges 80 80 bronze badges. Active Oldest Votes. David Lozzi David Lozzi 7, 3 3 gold badges 24 24 silver badges 50 50 bronze badges.

Farrukh Farrukh 1. Sign up or log in Sign up using Google.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. Is there a way to test if a URL matches an existing route? You should be able to use router. You can get the router instance from context like Link does or as the return value of Router.

It seems like the router object no longer has a match method with react-router 2. Is there a new way to do this? I would like to do a similar thing - show a specific piece of UI only if the current route matches a certain route pattern. You're looking for this. Thanks timdorr for the quick reply, but isActive doesn't work the way I had thought, and doesn't seem to work for my purpose. In fact, I submitted a patch yesterday assuming isActive was broken, but apparently I was just misunderstanding its API.

On the other hand, isActive assumes you're passing in a path rather than a path pattern, i. I'm trying to determine if a route pattern is currently active, not whether a particular URL is active which I can already determine with location.

To reiterate the original question for the new release, is there a way to test if an arbitrary route exists in react-router 2 now? Complicating this might be the new way to declare a not found page, which is to match all routes. This might mean a function for testing match may always return true with the not found route. You can use the match helper from the server-side rendering API.

Note that matching is not guaranteed to be synchronous, though, depending on your route configuration. Thanks taion. I tried match and indeed I had to pass a callback in to get the result, which complicates rendering a bit.

It also matched external URLs with the not found page I set up in routes currently the index page. So I would have to test whether the matched URL and its components is the same as the one I passed in to determine whether the route exists.

I'm not too familiar with react-router and the async routes stuff, so just wondering could there be a simpler and synchronous way, perhaps a builtin function on props. I guess this is more of a feature request now! That would mean that by just rendering a link to a route you would end up fetching the components even though they're not needed yet If the routes are all sync, then it will return synchronously.

Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle code editor.

It should be straightforward to wrap this in a synchronous function if those conditions are satisfied in your app, but this is specific enough that we don't want to include it in React Router. You can also add a property on your "not found" route and test against that to determine whether you matched it.

I understand that match needs to async load all the routes in order to test if the routes match. The issue is that match will load both the routes and the components via getComponents ideally there would be an api to be able to match without loading the components to be able to test if a path is a valid route. I agree with tikotzky — I would also like to see such a feature. My use-case is to use the setRouteLeaveHook to check if the next route is "valid" e.

But to do that I need to lookup which route the user is trying to go to. Skip to content. Code Issues 29 Pull requests 18 Security Pulse. Dismiss Join GitHub today GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.

Sign up.In React, you can create distinct components that encapsulate behavior you need. Then, you can render only some of them, depending on the state of your application. Conditional rendering in React works the same way conditions work in JavaScript.

Use JavaScript operators like if or the conditional operator to create elements representing the current state, and let React update the UI to match them. Try it on CodePen.

This example renders a different greeting depending on the value of isLoggedIn prop. You can use variables to store elements. In the example below, we will create a stateful component called LoginControl. While declaring a variable and using an if statement is a fine way to conditionally render a component, sometimes you might want to use a shorter syntax. There are a few ways to inline conditions in JSX, explained below. You may embed any expressions in JSX by wrapping them in curly braces.

It can be handy for conditionally including an element:. If it is falseReact will ignore and skip it. Another method for conditionally rendering elements inline is to use the JavaScript conditional operator condition? Just like in JavaScript, it is up to you to choose an appropriate style based on what you and your team consider more readable.

Also remember that whenever conditions become too complex, it might be a good time to extract a component. In rare cases you might want a component to hide itself even though it was rendered by another component. To do this return null instead of its render output. If the value of the prop is falsethen the component does not render:. For instance componentDidUpdate will still be called.

Edit this page.

SSIS - How to check if File Exists Or Not -- Script Task

Main Concepts. Advanced Guides. API Reference. Concurrent Mode Experimental. Previous article. Handling Events.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. I know it's super simple but that way I can use this library to show a loading progress bar or default image, and if the image fails to load it'll throw in the default image I provide.

react check if url exists

Yes this approach should work, the problem with the OP's code was that it was trying to change this. RoiDayan1 Did not work for me! Hi all, I have list uri of image in assets, how can i check if uri exist or not? I research but can not find a solution. Need the same functionality, I have a list of images and I need to dynamically update each if there's an error loading one of them with an alternative link the link is different for each image.

Tried RoiDayan1 method, but got the same as anuragprajapat : undefined is not an object evaluating this. You can also use defaultSource for this functionality. Dror-Bar srkirkland how to do that in case of image-url arrays.

react check if url exists

Not getting any way for that :. NarendraSingh88 Could you explain what's the problem exactly? RoiDayan1 solution is the best for customization I think.

react check if url exists

Just set up ref and we can control exactly each image element's source in case of error. Skip to content. Dismiss Join GitHub today GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.

Sign up. New issue. Jump to bottom. Copy link Quote reply. Hi folks, There is some way to do that? I'm trying with onError method but the image still loading.

If-Else in JSX

This comment has been minimized. Sign in to view. Full code export default class ImageWithDefault extends React. Same question. Convert Image source prop to use src if uri is broken. Yes that seems to be the ideal solution right now. This should be at top! In addition, remember replace "src" with "source" if you are working with iOS.From images to stylesheets to script files, what you see in your HTML document often involves a collection of files that work together to display the final result:.

For a static web page, this is business as usual. There is a link in the markup to the file you need, and this link never changes unless you make that change yourself.

When you preview in your browser, you can quickly tell if everything has loaded properly. As content becomes more and more dynamic, the files that your HTML document relies on are subject to change.

You may have a small script that generates a download link whose URL points to a file that was generated only moments ago. Your server might be running a framework that creates files on the fly for your HTML page to reference. To go all passive-tense on you, being able to verify whether a file exists before taking any further action would be very helpful. In this tutorial, we will examine the small amount of code that we can use to very easily check if a file exists using a technique that has existed since the beginning of the internet.

To use it in your application, just call the doesFileExist function and pass in the URL of the file you are checking the existence of. The function returns a true if the file exists, and it returns a false if the file doesn't exist. See, it's pretty simple! If all you came here was just for the code snippet on how to do this, you should have everything you need.

With that said, I don't want you to leave just yet. Check out the following section that explains why the code works the way it does in greater detail so that you can be smarter than your friends. Now that you have a working example, let's take a step back and figure out why the few lines of code that you have allow you to determine whether a file exists or not!

Let's start at the very top:. Our function is called doesFileExistand it takes one argument called urlToFile. The contents of this function are responsible for unicorns and creating a request that lets a server tell you whether a file exists or not.

The XMLHttpRequest class contains a lot of methods and properties that help us to ask a server whether a file exists or not. The URL value is stored by the urlToFile variable that is used to store the argument passed in to this function. The false argument is used to specify that you want this request to be made synchronously.

In other words, your application is blocked until you get a response back. If you set this value as truethe request is made asynchronously and your browser will continue running other parts of your code. While I am very pro-asynchronous, for what our code is doing, blocking everything until we get a response is the right thing.

The second line is important.


thoughts on “React check if url exists

Leave a Reply

Your email address will not be published. Required fields are marked *