Merge pull request #4 from jbgraug/master

added -e, --etag argument to inject filenames + ?etag=hash to avoid undesired caching in new deployments
jbgraug · Aug 22, 2017 · b26e724 · b26e724
2 parents 85fd3f2 + 309c947
commit b26e724
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Showing 2 changed files with 43 additions and 2 deletions.
diff --git a/postbuild b/postbuild
@@ -8,12 +8,24 @@ const path = require('path');
 const glob = require('glob');
 const replaceStream = require('replacestream');
 const program = require('commander');
+const crypto = require('crypto');
 
 let cssFiles;
 let jsFiles;
 let revision;
 let removeCondition;
 
+function appendETagSHAToFilename(filename){
+    if (program.etag) {
+        let sha = crypto.createHash('sha');
+        let fContent = fs.readFileSync(filename).toString();
+        sha.update(fContent);
+        return `${filename}?etag=${sha.digest('hex').toString()}`;
+    } else {
+        return filename;
+    }
+}
+
 const replaceFunc = replacement => {
     return function() {
         return replacement === undefined ? arguments[0] : replacement;
@@ -38,6 +50,7 @@ program
 .option('-r, --remove <remove>', 'Remove condition')
 .option('-g, --ignore <path>', 'Prefix to remove from the injected filenames')
 .option('-H, --hash', 'Inject git hash of current commit')
+.option('-e, --etag', 'appends "?etag=fileHash" to every import (link, script) to avoid undesired caching in new deployments')
 .parse(process.argv);
 
 if(!program.input) {
@@ -68,19 +81,21 @@ if(program.js) {
         if(glob.hasMagic(js)) {
              jsFiles = glob.sync(js)
              .map(file => removePrefix(file, program.ignore))
+             .map(file => appendETagSHAToFilename(file))
              .map(file => `<script src="${file}"></script>`)
              .join('\n');
         }
         else if(fs.lstatSync(js).isDirectory()) {
              jsFiles = fs.readdirSync(js)
              .filter(file => file.substr(-3) === '.js')
              .map(file => removePrefix(`${js}/${file}`, program.ignore))
+             .map(file => appendETagSHAToFilename(file))
              .map(file => `<script src="${file}"></script>`)
              .join('\n');
         }
         else if(fs.lstatSync(js).isFile()) {
             let file = removePrefix(js, program.ignore);
-            jsFiles = `<script src="${file}"></script>`;
+            jsFiles = `<script src="${appendETagSHAToFilename(file)}"></script>`;
         }
     }
     catch(e) {
@@ -95,19 +110,21 @@ if(program.css) {
         if(glob.hasMagic(css)) {
              cssFiles = glob.sync(css)
              .map(file => removePrefix(file, program.ignore))
+             .map(file => appendETagSHAToFilename(file))
              .map(file => `<link rel="stylesheet" href="${file}">`)
              .join('\n');
         }
         else if(fs.lstatSync(css).isDirectory()) {
             cssFiles = fs.readdirSync(css)
             .filter(file => file.substr(-4) === '.css')
             .map(file => removePrefix(`${css}/${file}`, program.ignore))
+            .map(file => appendETagSHAToFilename(file))
             .map(file => `<link rel="stylesheet" href="${file}">`)
             .join('\n');
         }
         else if(fs.lstatSync(css).isFile()) {
             let file = removePrefix(css, program.ignore);
-            cssFiles = `<link rel="stylesheet" href="${file}">`;
+            cssFiles = `<link rel="stylesheet" href="${appendETagSHAToFilename(file)}">`;
         }
     }
     catch(e) {

diff --git a/readme.md b/readme.md
@@ -51,6 +51,7 @@ This way you can replace the regular files used in a development environment wit
     -r, --remove <remove>  Remove condition
     -g, --ignore <path>    Prefix to remove from the injected filenames
     -H, --hash             Inject git hash of current commit
+    -e, --etag             Appends "?etag=fileHash" to every import (link, script) to avoid undesired caching in new deployments
 
 ### Examples
 
@@ -134,6 +135,29 @@ results in:
 
 *Notice that `vendor.js` is not injected.*
 
+If the -e, --etag is specified the output will be 
+
+```html
+   <!DOCTYPE html>
+   <html>
+   <head>
+     <title>Home</title>
+
+     <!-- inject:css -->
+     <link rel="stylesheet" href="dist/css/styles.1234abc.css?etag=e997365235369248a234b1c343ac41">
+     <!-- endinject -->
+
+   </head>
+   <body>
+
+     <!-- inject:js -->
+     <script src="dist/js/build.4567def.js?etag=9fffaf9de332d9848ab34bbc3434d34341"></script>
+     <!-- endinject -->
+
+   </body>
+   </html>
+```
+
 ### Tests
 
 Run `npm test` to run the tests.