(core) Showing links in text cells

Summary:
When there is a link in a text cell (and formula cells), it will be
rendered with a little clickable icon wrapped in the anchor tag
with a proper link. Only links that starts with https? will be
rendered as links.

Links are shown in a Text and Formula fields, inside a GridView,
CardView and in the Import preview dialog.

Test Plan: Browser tests

Reviewers: alexmojaki

Reviewed By: alexmojaki

Subscribers: dsagal, alexmojaki

Differential Revision: https://phab.getgrist.com/D3070

app/client/lib/textUtils.ts

@@ -0,0 +1,47 @@
+// There are many regex for matching URL, but non seem to be the correct solution.
+// Here we will use very fast and simple one.
+// Tested most of the regex solutions mentioned in this post
+// https://stackoverflow.com/questions/37684/how-to-replace-plain-urls-with-links.
+// The best one was http://alexcorvi.github.io/anchorme.js/, which still wasn't perfect.
+// The best non regex solution was https://github.com/Hypercontext/linkifyjs, but it feels a little too heavy.
+// Some examples why this is better or worse from other solution:
+/**
+
+For 'http://www.uk,http://www.uk'
+'OurRegex' [ 'http://www.uk', 'http://www.uk' ]
+'Anchrome' [ 'http://www.uk,http://www.uk' ]
+'linkify' [ 'http://www.uk,http://www.uk' ]
+'url-regex' [ 'http://www.uk', 'http://www.uk' ]
+
+For 'might.it be a link'
+'OurRegex' []
+'Anchrome' [ 'might.it' ]
+'linkify' [ 'http://might.it' ]
+'url-regex' []
+
+For 'Is this correct.No it is not'
+'OurRegex' []
+'Anchrome' [ 'correct.No' ]
+'linkify' [ 'http://correct.No' ]
+'url-regex' []
+
+For 'Link (in http://www.uk?)'
+'OurRegex' [ 'http://www.uk' ]
+'Anchrome' [ 'http://www.uk' ]
+'linkify' [ 'http://www.uk' ]
+'url-regex' [ 'http://www.uk?)' ]
+*/
+
+// Match http or https then domain name (with optional port) then any text that ends with letter or number.
+export const urlRegex = /(https?:\/\/[A-Za-z\d][A-Za-z\d-.]*(?!\.)(?::\d+)?(?:\/[^\s]*)?[\w\d/])/;
+
+/**
+ * Detects URLs in a text and returns list of tokens { value, isLink }
+ */
+export function findLinks(text: string): Array<{value: string, isLink: boolean}> {
+  if (!text) {
+    return [{ value: text, isLink: false }];
+  }
+  // urls will be at odd-number indices
+  return text.split(urlRegex).map((value, i) => ({ value, isLink : (i % 2) === 1}));
+}

app/client/ui2018/icons.ts

@@ -68,6 +68,15 @@ const iconDiv = styled('div', `
   background-color: var(--icon-color, black);
 `);
 
+export const cssIconBackground = styled(iconDiv, `
+  background-color: var(--icon-background, inherit);
+  -webkit-mask: none;
+  & .${iconDiv.className} {
+    transition: inherit;
+    display: block;
+  }
+`);
+
 export function icon(name: IconName, ...domArgs: DomElementArg[]): HTMLElement {
   return iconDiv(
     dom.style('-webkit-mask-image', `var(--icon-${name})`),

app/client/ui2018/links.ts

@@ -1,10 +1,12 @@
+import { sameDocumentUrlState, urlState } from 'app/client/models/gristUrlState';
+import { colors } from 'app/client/ui2018/cssVars';
+import { CellValue } from 'app/plugin/GristData';
+import { dom, IDomArgs, Observable, styled } from 'grainjs';
+
 /**
  * Styling for a simple green <A HREF> link.
  */
 
-import { colors } from 'app/client/ui2018/cssVars';
-import { styled } from 'grainjs';
-
 // Match the font-weight of buttons.
 export const cssLink = styled('a', `
   color: ${colors.lightGreen};
@@ -16,3 +18,31 @@ export const cssLink = styled('a', `
     text-decoration: underline;
   }
 `);
+
+export function gristLink(href: string|Observable<string>, ...args: IDomArgs<HTMLElement>) {
+  return dom("a",
+    dom.attr("href", href),
+    dom.attr("target", "_blank"),
+    dom.on("click", ev => onClickHyperLink(ev, typeof href === 'string' ? href : href.get())),
+    // As per Google and Mozilla recommendations to prevent opened links
+    // from running on the same process as Grist:
+    // https://developers.google.com/web/tools/lighthouse/audits/noopener
+    dom.attr("rel", "noopener noreferrer"),
+    args
+  );
+}
+
+/**
+ * If possible (i.e. if `url` points to somewhere in the current document)
+ * use pushUrl to navigate without reloading or opening a new tab
+ */
+export async function onClickHyperLink(ev: MouseEvent, url: CellValue) {
+  // Only override plain-vanilla clicks.
+  if (ev.shiftKey || ev.metaKey || ev.ctrlKey || ev.altKey) { return; }
+
+  const newUrlState = sameDocumentUrlState(url);
+  if (!newUrlState) { return; }
+
+  ev.preventDefault();
+  await urlState().pushUrl(newUrlState);
+}

app/client/widgets/HyperLinkTextBox.ts

@@ -1,11 +1,12 @@
-import {CellValue} from 'app/common/DocActions';
 import { DataRowModel } from 'app/client/models/DataRowModel';
 import { ViewFieldRec } from 'app/client/models/entities/ViewFieldRec';
+import { constructUrl } from 'app/client/models/gristUrlState';
 import { colors, testId } from 'app/client/ui2018/cssVars';
-import {icon} from 'app/client/ui2018/icons';
-import {NTextBox} from 'app/client/widgets/NTextBox';
-import {dom, styled} from 'grainjs';
-import {constructUrl, sameDocumentUrlState, urlState} from "app/client/models/gristUrlState";
+import { cssIconBackground, icon } from 'app/client/ui2018/icons';
+import { gristLink } from 'app/client/ui2018/links';
+import { cssHoverIn, NTextBox } from 'app/client/widgets/NTextBox';
+import { CellValue } from 'app/common/DocActions';
+import { Computed, dom, styled } from 'grainjs';
 
 /**
  * Creates a widget for displaying links.  Links can entered directly or following a title.
@@ -19,22 +20,19 @@ export class HyperLinkTextBox extends NTextBox {
 
   public buildDom(row: DataRowModel) {
     const value = row.cells[this.field.colId()];
+    const url = Computed.create(null, (use) => constructUrl(use(value)));
     return cssFieldClip(
+      dom.autoDispose(url),
       dom.style('text-align', this.alignment),
       dom.cls('text_wrapping', this.wrapping),
       dom.maybe((use) => Boolean(use(value)), () =>
-        dom('a',
-          dom.attr('href', (use) => constructUrl(use(value))),
-          dom.attr('target', '_blank'),
-          dom.on('click', (ev) =>
-              _onClickHyperlink(ev, value.peek())),
-          // As per Google and Mozilla recommendations to prevent opened links
-          // from running on the same process as Grist:
-          // https://developers.google.com/web/tools/lighthouse/audits/noopener
-          dom.attr('rel', 'noopener noreferrer'),
-          cssLinkIcon('FieldLink', testId('tb-link-icon')),
-          testId('tb-link')
-        )
+        gristLink(url,
+          cssIconBackground(
+            icon("FieldLink", testId('tb-link-icon')),
+            dom.cls(cssHoverOnField.className),
+          ),
+          testId('tb-link'),
+        ),
       ),
       dom.text((use) => _formatValue(use(value))),
     );
@@ -50,26 +48,8 @@ function _formatValue(value: CellValue): string {
   return index >= 0 ? value.slice(0, index) : value;
 }
 
-/**
- * If possible (i.e. if `url` points to somewhere in the current document)
- * use pushUrl to navigate without reloading or opening a new tab
- */
-async function _onClickHyperlink(ev: MouseEvent, url: CellValue) {
-  // Only override plain-vanilla clicks.
-  if (ev.shiftKey || ev.metaKey || ev.ctrlKey || ev.altKey) { return; }
-
-  const newUrlState = sameDocumentUrlState(url);
-  if (!newUrlState) { return; }
-
-  ev.preventDefault();
-  await urlState().pushUrl(newUrlState);
-}
-
 const cssFieldClip = styled('div.field_clip', `
   color: var(--grist-actual-cell-color, ${colors.lightGreen});
 `);
 
-const cssLinkIcon = styled(icon, `
-  background-color: var(--grist-actual-cell-color, ${colors.lightGreen});
-  margin: -1px 2px 2px 0;
-`);
+const cssHoverOnField = cssHoverIn(cssFieldClip.className);

app/client/widgets/NTextBox.ts

@@ -1,11 +1,14 @@
 import { fromKoSave } from 'app/client/lib/fromKoSave';
+import { findLinks } from 'app/client/lib/textUtils';
 import { DataRowModel } from 'app/client/models/DataRowModel';
 import { ViewFieldRec } from 'app/client/models/entities/ViewFieldRec';
 import { cssRow } from 'app/client/ui/RightPanel';
 import { alignmentSelect, makeButtonSelect } from 'app/client/ui2018/buttonSelect';
-import {testId} from 'app/client/ui2018/cssVars';
+import { colors, testId } from 'app/client/ui2018/cssVars';
+import { cssIconBackground, icon } from 'app/client/ui2018/icons';
+import { gristLink } from 'app/client/ui2018/links';
 import { NewAbstractWidget, Options } from 'app/client/widgets/NewAbstractWidget';
-import {dom, DomContents, fromKo, Observable} from 'grainjs';
+import { dom, DomArg, DomContents, fromKo, Observable, styled } from 'grainjs';
 
 /**
  * TextBox - The most basic widget for displaying text information.
@@ -42,13 +45,74 @@ export class NTextBox extends NewAbstractWidget {
     return dom('div.field_clip',
       dom.style('text-align', this.alignment),
       dom.cls('text_wrapping', this.wrapping),
-      dom.text((use) => use(row._isAddRow) ? '' : use(this.valueFormatter).format(use(value))),
+      dom.domComputed((use) => use(row._isAddRow) ? null : makeLinks(use(this.valueFormatter).format(use(value))))
     );
   }
 
-  private _toggleWrap(value: boolean) {
+  private _toggleWrap() {
     const newValue = !this.wrapping.get();
     this.options.update({wrap: newValue});
     (this.options as any).save();
   }
 }
+
+function makeLinks(text: string) {
+  try {
+    const domElements: DomArg[] = [];
+    for (const {value, isLink} of findLinks(text)) {
+      if (isLink) {
+        // Wrap link with a span to provide hover on and to override wrapping.
+        domElements.push(cssMaybeWrap(
+          gristLink(value,
+            cssIconBackground(
+              icon("FieldLink", testId('tb-link-icon')),
+              dom.cls(cssHoverInText.className),
+            ),
+          ),
+          linkColor(value),
+          testId("text-link")
+        ));
+      } else {
+        domElements.push(value);
+      }
+    }
+    return domElements;
+  } catch(ex) {
+    // In case when something went wrong, simply log and return original text, as showing
+    // links is not that important.
+    console.warn("makeLinks failed", ex);
+    return text;
+  }
+}
+
+// For links we want to break all the parts, not only words.
+const cssMaybeWrap = styled('span', `
+  white-space: inherit;
+  .text_wrapping & {
+    word-break: break-all;
+    white-space: pre-wrap;
+  }
+`);
+
+// A gentle transition effect on hover in, and the same effect on hover out with a little delay.
+export const cssHoverIn = (parentClass: string) => styled('span', `
+  --icon-color: var(--grist-actual-cell-color, ${colors.lightGreen});
+  margin: -1px 2px 2px 0;
+  border-radius: 3px;
+  transition-property: background-color;
+  transition-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
+  transition-duration: 150ms;
+  transition-delay: 90ms;
+  .${parentClass}:hover & {
+    --icon-background: ${colors.lightGreen};
+    --icon-color: white;
+    transition-duration: 80ms;
+    transition-delay: 0ms;
+  }
+`);
+
+const cssHoverInText = cssHoverIn(cssMaybeWrap.className);
+
+const linkColor = styled('span', `
+  color: var(--grist-actual-cell-color, ${colors.lightGreen});;
+`);