Fossil

# The fileedit Page

This document describes the limitations of, caveats for, and
disclaimers for the [](/fileedit) page, which provides users with
[checkin privileges](./caps/index.md) basic editing features for files
via the web interface.

# Important Caveats and Disclaimers

Predictably, the ability to edit files in a repository from a web
browser halfway around the world comes with several obligatory caveats
and disclaimers...

## <a id="cap"></a> `/fileedit` Does *Nothing* by Default.

In order to "activate" it, a user with [the "setup"
permission](./caps/index.md) must set the
[fileedit-glob](/help?cmd=fileedit-glob) repository setting to a
comma- or newline-delimited list of globs representing a whitelist of
files which may be edited online. Any user with commit access may then
edit files matching one of those globs. Certain pages within the UI
get an "edit" link added to them when the current user's permissions
and the whitelist both permit editing of that file.

## <a id="csrf"></a> CSRF & HTTP Referrer Headers

In order to protect against [Cross-site Request Forgery (CSRF)][csrf]
attacks, Fossil UI features which write to the database require that
the browser send the so-called [HTTP `Referer` header][referer]
(noting that the misspelling of "referrer" is a historical accident
which has long-since been standardized!). Modern browsers, by default,
include such information automatically for *interactive* actions which

connections. Fossil does not offer a way to disable its CSRF
protections.

[referer]: https://en.wikipedia.org/wiki/HTTP_referer
[csrf]: https://en.wikipedia.org/wiki/Cross-site_request_forgery
[xhr]: https://en.wikipedia.org/wiki/XMLHttpRequest

## <a id="commit"></a> `/fileedit` **Works by Creating Commits**

Thus any edits made via that page become a normal part of the
repository.

## <a id="intent"></a> `/fileedit` is *Intended* for use with Embedded Docs

... and similar text files, and is most certainly
**not intended for editing code**.

Editing files with unusual syntax requirements, e.g. hard tabs in
makefiles, may break them. *You Have Been Warned.*

Similarly, though every effort is made to retain the end-of-line
style used by being-edited files, the round-trip through an HTML
textarea element may change the EOLs. The Commit section of the page
offers three different options for how to treat newlines when saving
changes. **Files with mixed EOL styles** *will be normalized to a single
EOL style* when modified using `/fileedit`. When "inheriting" the EOL
style from a previous version which has mixed styles, the first EOL
style detected in the previous version of the file is used.

## <a id="checkout"></a> `/fileedit` **is Not a Replacement for a Checkout**

A full-featured checkout allows far more possibilities than this basic
online editor permits, and the feature scope of `/fileedit` is
intentionally kept small, implementing only the bare necessities
needed for performing basic edits online. It *is not, and will never
be, a replacement for a checkout.*

Similarly, some *potential* features have significant downsides,
abuses, and/or implementation hurdles which make the decision of
whether or not to implement them subject to notable contributor
debate. e.g. the ability to add new files or remove/rename older
files.


## <a id="storage"></a> `/fileedit` **Stores Only Limited Local Edits While Working**

When changes are made to a given checkin/file combination,
`/fileedit` will, if possible, store them in [`window.localStorage`
or `window.sessionStorage`][html5storage], if available, but...

- Which storage is used is unspecified and may differ across
  environments.

across reloads of the same tab.

If `/filepage` determines that no peristent storage is available a
warning is displayed on the editor page.

[html5storage]: https://developer.mozilla.org/en-US/docs/Web/API/Web_Storage_API

## <a id="power"></a> The Power is Yours, but...

> "With great power comes great responsibility."

**Use this feature judiciously, *if at all*.**

Now, with those warnings and caveats out of the way...

-----

# <a id="tips"></a> Tips and Tricks

## <a id="global-js"></a> `fossil` Global-scope JS Object

`/fileedit` is largely implemented in JavaScript, and makes heavy use
of the global-scope `fossil` object, which provides
infrastructure-level features intended for use by Fossil UI pages.
(That said, that infrastructure was introduced with `/fileedit`, and
most pages do not use it.)

The `fossil.page` object represents the UI's current page (on pages
which make use of this API - most do not). That object supports
listening to page-specific events so that JS code installed via
[client-side edits to the site skin's footer](customskin.md) may react
to those changes somehow. The next section describes one such use for
such events...

## <a id="syn-hl"></a> Integrating Syntax Highlighting

Assuming a repository has integrated a 3rd-party syntax highlighting
solution, it can probably (depending on its API) be told how to
highlight `/fileedit`'s wiki/markdown-format previews. Here are
instructions for doing so with [highlightjs](https://highlightjs.org/):

At the very bottom of the [site skin's footer](customskin.md), add a

  by Fossil (by its file extension).

The event listener callback shown above doesn't use the `mimetype`,
but makes used of the other two. It fishes all `code` blocks out of
the preview which explicitly have a CSS class named
`language-`something, and then asks highlightjs to highlight them.

## <a id="editor"></a> Integrating a Custom Editor Widget

(These instructions also work for the `/wikiedit` page by eplacing
"fileedit" with "wikiedit" in any strings or symbol names!)

It is possible to replace `/filepage`'s basic text-editing widget (a
`textarea` element) with a fancy 3rd-party editor widget by following
these instructions...