refactor: replace gulp by webpack and npm scripts (#258)

BREAKING CHANGE: We have replaced `gulp` with `webpack` and `npm scripts` to build this theme. If you build it on your own or use build commands during the deployment, you may have to adjust your setup.

BREAKING CHANGE: The `GeekblogIcons` font is using the icon name as Unicode now. As a consequence, you have to replace all references to Icons from this font if you have customized the theme.

BREAKING CHANGE: We have refactored the search integration to split Hugo templates from JavaScript code. To get it working again, you need to adjust the `outputFormats` and `outputs` in your Hugo configuration file, as [documented](https://geekdocs.de/usage/configuration/#site-configuration).

1 files changed, 57 insertions, 0 deletions

diff --git a/webpack.plugins.js b/webpack.plugins.js
new file mode 100644
index 0000000..b7d48b9
--- /dev/null
+++ b/webpack.plugins.js
@@ -0,0 +1,57 @@
+const fs = require("fs")
+const crypto = require("crypto")
+const path = require("path")
+const { validate } = require("schema-utils")
+
+class SRIPlugin {
+  static defaultOptions = {
+    algorithm: "sha512",
+    sourceFile: "assets.json"
+  }
+
+  constructor(options = {}) {
+    const schema = {
+      type: "object",
+      properties: {
+        outputFile: {
+          type: "string"
+        },
+        algorithm: {
+          type: "string"
+        }
+      }
+    }
+
+    this.options = { ...SRIPlugin.defaultOptions, ...options }
+
+    validate(schema, options, {
+      name: "SRI Plugin",
+      baseDataPath: "options"
+    })
+  }
+
+  apply(compiler) {
+    compiler.hooks.done.tap("SRIPlugin", (manifest) => {
+      let data = JSON.parse(fs.readFileSync(this.options.sourceFile, "utf8"))
+      let outputFile = this.options.outputFile ? this.options.outputFile : this.options.sourceFile
+
+      const checksum = (str, algorithm = this.options.algorithm, encoding = "base64") =>
+        crypto.createHash(algorithm).update(str, "utf8").digest(encoding)
+      const fileSum = (file, algorithm) => checksum(fs.readFileSync(file), algorithm)
+      const calculateSRI = (file, algorithm = this.options.algorithm) =>
+        `${algorithm}-${fileSum(path.join(".", "static", file), algorithm)}`
+
+      Object.keys(data).forEach((key) => {
+        let element = data[key]
+        element.integrity = calculateSRI(element.src)
+      })
+
+      fs.writeFileSync(outputFile, JSON.stringify(data, null, 2), {
+        encoding: "utf8",
+        flag: "w"
+      })
+    })
+  }
+}
+
+module.exports = SRIPlugin