Refactor ContentMetadata into ResponseMetaData.

1 files changed, 54 insertions, 0 deletions

diff --git a/src/lib/ResponseMetaData.js b/src/lib/ResponseMetaData.js
new file mode 100644
index 0000000..17e1608
--- /dev/null
+++ b/src/lib/ResponseMetaData.js
@@ -0,0 +1,54 @@
+class ResponseMetaData {
+  constructor(request) {
+    let {responseHeaders} = request;
+    this.headers = {};
+    this.contentType = this.contentDisposition = null;
+    for (let h of responseHeaders) {
+      if (/^\s*Content-(Type|Disposition)\s*$/i.test(h.name)) {
+        let propertyName = RegExp.$1;
+        propertyName = `content${propertyName.charAt(0).toUpperCase()}${propertyName.substring(1).toLowerCase()}`;
+        this[propertyName] = h.value;
+        this.headers[propertyName] = h;
+      }
+    }
+    this.forcedUTF8 = false;
+  }
+
+  get charset() {
+    let charset = "";
+    if (this.contentType) {
+      let m = this.contentType.match(/;\s*charset\s*=\s*(\S+)/);
+      if (m) {
+        charset = m[1];
+      }
+    }
+    Object.defineProperty(this, "charset", { value: charset, writable: false, configurable: true });
+    return charset;
+  }
+
+  get isUTF8() {
+    return /^utf-8$/i.test(this.charset);
+  }
+
+  forceUTF8() {
+    if (!(this.forcedUTF8 || this.isUTF8)) {
+      let h = this.headers.contentType;
+      if (h) {
+        h.value = h.value.replace(/;\s*charset\s*=.*|$/, "; charset=utf8");
+        this.forcedUTF8 = true;
+      } // if the header doesn't exist the browser should default to UTF-8 anyway
+    }
+    return this.forcedUTF8;
+  }
+
+  createDecoder() {
+    if (this.charset) {
+      try {
+        return new TextDecoder(this.charset);
+      } catch (e) {
+        console.error(e);
+      }
+    }
+    return new TextDecoder("utf-8");
+  }
+};