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79 lines
2.2 KiB
79 lines
2.2 KiB
4 years ago
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# isBinaryFile
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Detects if a file is binary in Node.js. Similar to [Perl's `-B` switch](http://stackoverflow.com/questions/899206/how-does-perl-know-a-file-is-binary), in that:
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- it reads the first few thousand bytes of a file
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- checks for a `null` byte; if it's found, it's binary
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- flags non-ASCII characters. After a certain number of "weird" characters, the file is flagged as binary
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Much of the logic is pretty much ported from [ag](https://github.com/ggreer/the_silver_searcher).
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Note: if the file doesn't exist, is a directory, or is empty, the function returns `false`.
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## Installation
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```
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npm install isbinaryfile
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```
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## Usage
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### isBinaryFile(filepath, callback)
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* `filepath`, a `string` indicating the path to the file.
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* `callback`, a `function` for the callback. It has two arguments:
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- `err`, the typical Node.js error argument
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- `result`, a `boolean` of `true` or `false`, depending on if the file is binary
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### isBinaryFile(bytes, size, callback)
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* `bytes`, a `Buffer` of the file's contents.
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* `size`, an optional `number` indicating the file size.
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* `callback`, a `function` for the callback. It has two arguments:
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- `err`, the typical Node.js error argument
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- `result`, a `boolean` of `true` or `false`, depending on if the file is binary
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### isBinaryFile.sync(filepath)
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* `filepath`, a `string` indicating the path to the file.
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### isBinaryFile.sync(bytes, size)
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* `bytes`, a `Buffer` of the file's contents.
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* `size`, an `number` indicating the file size.
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Returns a `boolean` of `true` or `false`, depending on if the file is binary.
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### Examples
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```javascript
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var isBinaryFile = require("isbinaryfile");
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fs.readFile("some_file", function(err, data) {
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fs.lstat("some_file", function(err, stat) {
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isBinaryFile(data, stat.size, function (err, result) {
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if (!err) {
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if (result) {
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console.log("It is!")
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}
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else {
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console.log("No.")
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}
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}
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});
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});
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});
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isBinaryFile.sync("some_file"); // true or false
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var bytes = fs.readFileSync(("some_file"));
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var size = fs.lstatSync(("some_file").size;
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isBinaryFile.sync(bytes, size); // true or false
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```
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## Testing
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Run `npm install` to install `mocha`, then run `npm test`.
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