Blob !!TOP!! Download React
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The Blob object represents a blob, which is a file-like object of immutable, raw data; they can be read as text or binary data, or converted into a ReadableStream so its methods can be used for processing the data.
Blobs can represent data that isn't necessarily in a JavaScript-native format. The File interface is based on Blob, inheriting blob functionality and expanding it to support files on the user's system.
To construct a Blob from other non-blob objects and data, use the Blob() constructor. To create a blob that contains a subset of another blob's data, use the slice() method. To obtain a Blob object for a file on the user's file system, see the File documentation.
One of the most popular methods for handling files and data fetched from the cloud is the blob, or binar large object. In this post, we'll explore how to fetch and handle blob data in React Native applications properly.
This package library covers all aspects of blob data management and the fetch API necessary for any project. Nevertheless, we'll provide you with a basic fetch alternative implemented in Expo in case your requirements are more basic.
According to Wikipedia: "A binary large object (BLOB or blob) is a collection of binary data stored as a single entity. Blobs are typically images, audio, or other multimedia objects, though sometimes binary executable code is stored as a blob."
What this means is that a blob is essentially a container for data, so it's more easily handled by protocols that fetch and manipulate large media files. So, if you're planning on working in an application with limited resources handling media files like photos or music, you'll be handling blobs.
Currently I am using rn-fetch-blob to store images I've downloaded. However, the library is no longer maintained. If anyone is still using this library have you run into any issues? For those who have stopped using it, are there any other alternate libraries I should be considering?
This is where the react-native-fs and react-native-blob-util packages come into play. These packages provide native file system access for React Native. In other words, they make file access and data transfer more accessible and efficient for React Native developers, especially for large files like blobs.
In the above code, the array is the blob string value, object values, or a mix of the values we want to convert to a blob. The options include the blob types (mime-type) which can be application/json, text/plain, image/png, and so on.
This will automatically add the react-native-fs package to our project. In a scenario where the automatic linking does not work for some reason, check the official docs to see how to manually link the package to your project.
In the code above, we import DocumentDirectoryPath and writeFile from our react-native-fs package. We use the DocumentDirectoryPath constant to get the directory file path of the location where we want to save our file. Then, we use the writeFile method to save our file with the content of our input.
This package is a fork of the now-deprecated react-native-fetch-blob package and its first fork, rn-fetch-blob. Since those packages are no longer maintained, the creator continued the project in this fork to go on supporting React Native developers in accessing and transferring data and files easily and efficiently.
Next, we create a function that will handle saving the file when we click the Create new file button. Just like react-native-fs, react-native-blob-util has a writeFile method that allows us to write and save a file to the path we specified.
To get the list of files in a directory, react-native-blob-util has a method called lstat that allows us to get the statistical data of files in a directory. The result data will be an array of objects; it also returns a promise.
With the returned objects, we can map through and display the file names. We can also accomplish other tasks, like checking the last modified date and time as well as the size of the files. See the code below to understand how this works in action:
Downloading a PDF blob is similar to downloading an image blob. We only make a tweak of the mime config and change the file name with a .pdf extension to indicate that we are downloading a PDF. See the code below;
We explored using these packages to create, save, and read files. We also saw how we can fetch and manage blobs in React Native, including uploading and downloading blobs from the cloud. During this process, we can perform a device storage check to provide better user experiences.
If you followed along with this tutorial and practiced the demonstrated examples, you should find it easy to fetch and handle blob data in React Native on your own using react-native-fs and react-native-blob-util. Be sure to comment with any questions you have while applying this knowledge to your projects.
Azure blob storage offers the ability to host your static site directly from an Azure Storage account. If you would like to get started setting up a static website with this option, follow the getting started tutorial.
If you have existing code that uses whatwg-fetch(the official fetch), it's not necessary to replace them with RNFetchblob.fetch, you can simply use our Fetch Replacement. The difference between Official them is official fetch uses whatwg-fetch which wraps XMLHttpRequest polyfill under the hood. It's a great library for web developers, but does not play very well with RN. Our implementation is simply a wrapper of our fetch and fs APIs, so you can access all the features we provided.
By default, react-native-fetch-blob does NOT allow connection to unknown certification provider since it's dangerous. To connect a server with self-signed certification, you need to add trusty to config explicitly. This function is available for version >= 0.5.3
Enable or disable automatic upload of images represented by data URLs or blob URIs. Such images get generated, for example, as a result of image manipulation through Image Tools plugin, or after image is drag-n-dropped onto the editor from the desktop.
Note: The images_dataimg_filter option can also be used to specify a filter predicate function for disabling the logic that converts base64 images into blobs while within the editor. Tiny discourages using images_dataimg_filter for this purpose.
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