How do you create a file from a string in Gulp?

问题:

In my gulpfile I have a version number in a string. I'd like to write the version number to a file. Is there a nice way to do this in Gulp, or should I be looking at more general NodeJS APIs?

回答1:

If you'd like to do this in a gulp-like way, you can create a stream of "fake" vinyl files and call pipe per usual. Here's a function for creating the stream. "stream" is a core module, so you don't need to install anything:

function string_src(filename, string) {
  var src = require('stream').Readable({ objectMode: true })
  src._read = function () {
    this.push(new gutil.File({
      cwd: "",
      base: "",
      path: filename,
      contents: new Buffer(string)
    }))
    this.push(null)
  }
  return src
}

You can use it like this:

gulp.task('version', function () {
  var pkg = require('package.json')
  return string_src("version", pkg.version)
    .pipe(gulp.dest('build/'))
})

回答2:

It's pretty much a one-liner in node:

require('fs').writeFileSync('dist/version.txt', '1.2.3');

Or from package.json:

var pkg = require('./package.json');
var fs = require('fs');
fs.writeFileSync('dist/version.txt', 'Version: ' + pkg.version);

---

I'm using it to specify a build date in an easily-accessible file, so I use this code before the usual return gulp.src(...) in the build task:

require('fs').writeFileSync('dist/build-date.txt', new Date());

回答3:

This can also be done with vinyl-source-stream. See this document in the gulp repository.

var gulp = require('gulp'),
    source = require('vinyl-source-stream');

gulp.task('some-task', function() {
    var stream = source('file.txt');

    stream.end('some data');
    stream.pipe(gulp.dest('output'));
});

回答4:

According to the maintainer of Gulp, the preferred way to write a string to a file is using fs.writeFile with the task callback.

var fs = require('fs');
var gulp = require('gulp');

gulp.task('taskname', function(cb){
  fs.writeFile('filename.txt', 'contents', cb);
});

Source: https://github.com/gulpjs/gulp/issues/332#issuecomment-36970935

回答5:

You can also use gulp-file:

var gulp = require('gulp');
var file = require('gulp-file');

gulp.task('version', function () {
    var pkg = require('package.json')

    return gulp.src('src/**')
        .pipe(file('version', pkg.version))
        .pipe(gulp.dest('build/'))
});

or without using gulp.src():

gulp.task('version', function () {
    var pkg = require('package.json')

    return file('version', pkg.version, {src: true})
        .pipe(gulp.dest('build/'))
});

回答6:

The gulp-header package can be used to prefix files with header banners.

eg. This will inject a banner into the header of your javascript files.

var header = require('gulp-header');
var pkg = require('./package.json');
var banner = ['/**',
  ' * <%= pkg.name %> - <%= pkg.description %>',
  ' * @version v<%= pkg.version %>',
  ' * @link <%= pkg.homepage %>',
  ' * @license <%= pkg.license %>',
  ' */',
  ''].join('\n');

gulp.src('./foo/*.js')
  .pipe(header(banner, { pkg: pkg } ))
  .pipe(gulp.dest('./dist/')

Gulp is a streaming build system leveraging pipes.

If you simply want to write a new file with an arbitrary string, you can use built in node fs object.

回答7:

This can also be achieved using gulp-tap

This can be especially helpful if you have identified multiple files that require this header. Here is relevant code (Also from gulp-tap documentation)

var gulp = require('gulp'),
    tap = require('gulp-tap');

gulp.src("src/**")
    .pipe(tap(function(file){
           file.contents = Buffer.concat([
             new Buffer('Some Version Header', 'utf8'),
             file.contents
           ]);
         }))
    .pipe(gulp.dest('dist');

回答8:

Using the string-to-stream and vinyl-source-stream modules:

var str = require('string-to-stream');
var source = require('vinyl-source-stream');
var gulp = require('gulp');

str('1.4.27').pipe(source('version.txt')).pipe(gulp.dest('dist'));