Support bootstrapping URL, debug and stage from URL params

ui/src/config.ts

@@ -1,10 +1,12 @@
 import { Writable, writable } from 'svelte/store';
+import { debugFromParams, debugStageFromParams } from './processParameters';
 
-export const debugEnabled = storedWritable('debugEnabled', false);
+export const debugEnabled = storedWritable('debugEnabled', false, debugFromParams);
-export const debugStage = storedWritable('debugStage', 0);
+export const debugStage = storedWritable('debugStage', 0, debugStageFromParams);
 
-function storedWritable<T>(key: string, defaultValue: T): Writable<T> {
+function storedWritable<T>(key: string, defaultValue: T, paramLoadFunction: (defaultValue: T) => T): Writable<T> {
-    const store = writable(fromLocalStore(key, defaultValue));
+    const value = paramLoadFunction(fromLocalStore(key, defaultValue));
+    const store = writable(value);
     store.subscribe((value) => {
         localStorage.setItem(key, JSON.stringify(value));
     });

ui/src/main/Upload.svelte

@@ -7,12 +7,21 @@
     import ProgressRing from '../components/ProgressRing.svelte';
     import Checkbox from '../components/Checkbox.svelte';
     import { debugEnabled } from '../config';
+    import { urlFromParams } from '../processParameters';
 
     let specifiedFileName: string;
     let dragover = false;
     let upload: Promise<any>;
     let rejectionError: string;
     let parseProgress: Progress;
+
+    const url = urlFromParams();
+    if (url) {
+        dragover = true;
+        specifiedFileName = url;
+        upload = loadUrl(handleProgress, url);
+    }
+
     function handleUrlLoad() {
         dragover = true;
         let answer = prompt('Url of the pdf');

ui/src/processParameters.ts

@@ -0,0 +1,26 @@
+const params = new URLSearchParams(window.location.search);
+
+export function debugFromParams(defaultValue: boolean): boolean {
+    const defined = params.has('debug');
+    if (!defined) {
+        return defaultValue;
+    }
+    return params.get('debug') !== 'false';
+}
+
+export function debugStageFromParams(defaultValue: number): number {
+    const stage = +params.get('stage');
+    if (!Number.isInteger(stage)) {
+        return defaultValue;
+    }
+    return stage;
+}
+
+export function urlFromParams(): string {
+    return getParameterByName('url');
+}
+
+function getParameterByName(name: string): string {
+    const match = RegExp('[?&]' + name + '=([^&]*)').exec(window.location.search);
+    return match && decodeURIComponent(match[1].replace(/\+/g, ' '));
+}