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Re: How to copy & read a huge zipped book with thousands of html & jpeg files

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Andy Burns wrote:
> Maria Sophia wrote:
> 
>> May I ask how long it took you and your team to arrive at that conclusion
>> and more importantly, what server mechanism you employed, if it's a free ad
>> free easily available web server, because the Termux method has issues too.
> 
> Spent a few hours trying to create working content:// URLs, but when 
> that didn't work out, used AWebServer, an android build of apache httpd 
> with a minimal GUI ...
> 
> <https://play.google.com/store/apps/details?id=com.sylkat.apache>
> 
> In the end we paid the developer to produce a custom build that
> 1) auto started the web server
> and 2) let us set our own document root
> 
> It looks like the latest version has included ftp, mySQL and myPHPadmin

Hi Andy,\

Thank you for your kind and detailed reply, as Usenet is to not only ask
questions, but to also help everyone lurking not make our same mistakes.

When Android dropped POSIX, Linux again saved the day with localhost HTTP!

It was a painful time-consuming lesson for me, but mainly because I had
trusted that Android was Linux-like when it came to the basic POSIX paths.

Your answer will help save others countless hours of debugging time.
And your answer helps me determine if I should invest in testing it out.

I like what the content of says about how it can help all of us carry on
our mobile devices custom HTML content containing relative filespec paths.
 <https://play.google.com/store/apps/details?id=com.sylkat.apache>
  AWebServer: Apache,PHP,SQL,SSH
  You can explore the files with any SO or browser through wireless.
  AWebServer is an easy and friendly solution to publish your own web in  
  your Android device with PHP and all the features that Apache brings.
  MariaDb the old Mysql sql server is also included and the MyPhpAdmin  
  application has been installed and ready to work with.
  Has integrated a FTP server to upload the contents and is compatible with  
  The Web Server is ready to use and has these features:
  +Apache 2, +Php 7, +MariaDb, +MyPhpAdmin, +Indexes Options, +Ftp server,
  +Logs viewer, +Text Editor.
  This app is based on the famous and stable Apache 2 server, known by its  
  stability in Android devices. Any question or feature request, 
  please send a mail to the developer kryzoxy@gmail.com

It seems your description of how your team solved the non-POSIX problem
aligns pretty much with what I observed. Unfortunately for those of us who
want to use POSIX-compliant paths in documentation, Android 10+
fundamentally changed how applications are allowed to access shared
storage. Anything that is not one of the four SAF-approved public
collections (Download, Documents, DCIM, Pictures) is no longer exposed to
WebView as a real POSIX path. 

Instead, WebView receives a synthetic SAF content URI such as:
content://com.android.externalstorage.documents/document/primary%3A0000%2Fbook%2Fname%2Findex.html
But this is not a directory. It is a virtual document handle. 

We learned the hard what that, because WebView never receives the actual
filesystem path, it cannot perform POSIX operations such as open(), stat(),
or opendir() on the underlying directory tree. As a result, any HTML manual
that relies on normal relative links (pages/2.html, images/foo.png,
css/style.css) immediately breaks. Every browser attempt to resolve these
links relative to the SAF URI inevitably produces invalid paths such as:
content://com.android.externalstorage.documents/document/pages/2.html
which, we found out the hard way, do not correspond to any file on disk. 

WebView then throws ERR_ACCESS_DENIED or ERR_FILE_NOT_FOUND which we have
to debug is only because the browser cannot traverse the non-POSIX
directory hierarchy. In effect, the browser appears to be sandboxed inside
a synthetic namespace with no ability to follow POSIX-style relative paths.

This hypothesis may explain why the manual opened perfectly on Windows (and
would have opened on Linux too), but failed on Android 16 in any browser. 

The HTML book expects a normal Unix directory structure, but Android 10+
hides that structure behind SAF, much like iOS hides their file specs too.

Since I only came up with the idea last night after a couple of hours of
debugging, it's helpful to note that your team's solution and mine converge
on the same principle, which is to bypass WebView's file:// restrictions
entirely by serving the manual over HTTP. 

The reason this works is that HTTP requests do not go through SAF, so the
browser finally sees the real directory tree. 

In your case, you used AWebServer (an Android build of Apache httpd). 
In my case, I used Termux with Python's built-in HTTP server:
 $ pkg install python
 Manually give Python storage access permissions as it doesn't ask.
 Then set the $DOCUMENT_ROOT by starting the server at the top level
 $ cd /storage/emulated/0/0000/book/name
 $ python3 -m http.server 8000

Then, in any privacy-based web browser, I simply set this bookmark:
 <http://localhost:8000>

At that point everything worked exactly as intended. All relative links,
images, CSS, and subpages loaded correctly because the browser was now
talking to a real POSIX-backed directory via HTTP instead of a SAF virtual
document tree.

Comparing the two approaches, your solution is far better'n mine is:
 a. You have a full Apache httpd stack
 b. Your solution has nice GUI controls
 c. Your solution can auto-start
 d. Your solution has a customizable document root
Hence, your solution works in production or institutional deployments.

Compared to mine, your solution is heavyweight but robust as all hell.
I can see why it's good for fire engines, kiosks & embedded deployments
And your solution supports additional services (FTP, MySQL, PHP) if needed

By way of stark contrast, the solution I came up with (Termux + Python):
 a. Is as lightweight as I could make it
 b. With almost zero configuration (other than the starting directory)
 c. Yet, like yours, it creates a pure POSIX environment
 d. Which is good for my Windows/Linux-style adb-scripted workflows

Unfortunately, my solution has none of the GUI, auto-start & service
management of your solution, but it has a minimal attack surface and it's
easy to script and automate if I wish, so it's OK for ad hoc servers.

The takeaway for the team to learn from our trials and tribulations is that 
both approaches solve the same underlying problem that Android 10+ broke
direct POSIX file:// access for custom top-level directories.

Luckily, our solution of localhost HTTP restores normal Unix semantics.

In summary, for those wishing to learn from our investment in testing,
Android browsers cannot directly open HTML manuals from custom directories
anymore because SAF hides the real filesystem. 

Luckily, a localhost HTTP server bypasses SAF to restore POSIX behavior.

Your team's experience confirms the diagnosis and validates the workaround.
I appreciate you sharing the details, especially the fact that you
eventually commissioned a custom build of AWebServer to auto-start and set
the document root. That is extremely useful information for anyone out
there who is deploying large HTML documentation sets in the field.

Thanks again for the insight. This thread will save others the hours we
both invested in rediscovering the same SAF limitations independently.
-- 
POSIX paths died on Android 10+, but localhost HTTP brings them back!

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Thread

How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-04 18:40 -0400
  Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-04 21:17 -0400
    Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-04 21:48 -0400
      Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-04 22:51 -0400
        Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-04 23:57 -0400
          Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-04 23:13 -0600
            Re: How to copy & read a huge zipped book with thousands of html & jpeg files Nuno Silva <nunojsilva@invalid.invalid> - 2026-07-08 10:10 +0100
              Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-08 10:32 -0400
          Re: How to copy & read a huge zipped book with thousands of html & jpeg files "Carlos E. R." <robin_listas@es.invalid> - 2026-07-05 13:29 +0200
            Re: How to copy & read a huge zipped book with thousands of html & jpeg files Dave Royal <dave@dave123royal.com> - 2026-07-05 14:48 +0100
              Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-05 10:06 -0600
              Re: How to copy & read a huge zipped book with thousands of html & jpeg files "Carlos E. R." <robin_listas@es.invalid> - 2026-07-05 19:10 +0200
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files Computer Nerd Kev <not@telling.you.invalid> - 2026-07-05 17:37 +0000
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files Alan <nuh-uh@nope.com> - 2026-07-07 11:11 -0700
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files Dave Royal <dave@dave123royal.com> - 2026-07-05 21:00 +0100
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files "Carlos E. R." <robin_listas@es.invalid> - 2026-07-05 22:50 +0200
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-05 23:06 -0600
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files "Carlos E. R." <robin_listas@es.invalid> - 2026-07-06 12:05 +0200
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files "Carlos E. R." <robin_listas@es.invalid> - 2026-07-06 12:24 +0200
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-06 10:28 -0600
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files "Carlos E. R." <robin_listas@es.invalid> - 2026-07-06 19:50 +0200
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-06 09:36 -0600
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files "Carlos E. R." <robin_listas@es.invalid> - 2026-07-06 19:56 +0200
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-08 11:14 -0400
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files Dave Royal <dave@dave123royal.com> - 2026-07-06 07:58 +0100
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files "Carlos E. R." <robin_listas@es.invalid> - 2026-07-06 12:12 +0200
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-05 15:12 -0600
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files Chris <ithinkiam@gmail.com> - 2026-07-08 17:51 +0000
              Re: How to copy & read a huge zipped book with thousands of html & jpeg files Chris <ithinkiam@gmail.com> - 2026-07-08 17:44 +0000
            Re: How to copy & read a huge zipped book with thousands of html & jpeg files Nuno Silva <nunojsilva@invalid.invalid> - 2026-07-08 10:39 +0100
          Re: How to copy & read a huge zipped book with thousands of html & jpeg files Nuno Silva <nunojsilva@invalid.invalid> - 2026-07-08 10:37 +0100
        Re: How to copy & read a huge zipped book with thousands of html & jpeg files Arno Welzel <usenet@arnowelzel.de> - 2026-07-06 17:53 +0200
          Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-06 10:47 -0600
          Re: How to copy & read a huge zipped book with thousands of html & jpeg files Nuno Silva <nunojsilva@invalid.invalid> - 2026-07-08 10:57 +0100
      Re: How to copy & read a huge zipped book with thousands of html & jpeg files Andy Burns <usenet@andyburns.uk> - 2026-07-05 08:35 +0100
        Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-05 10:38 -0600
          Re: How to copy & read a huge zipped book with thousands of html & jpeg files Andy Burns <usenet@andyburns.uk> - 2026-07-05 18:22 +0100
            Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-05 12:16 -0600
          Re: How to copy & read a huge zipped book with thousands of html & jpeg files "Carlos E. R." <robin_listas@es.invalid> - 2026-07-05 19:41 +0200
            Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-05 12:54 -0600
              Re: How to copy & read a huge zipped book with thousands of html & jpeg files "Carlos E. R." <robin_listas@es.invalid> - 2026-07-05 23:11 +0200
                Re: How to copy & read a huge zipped book with thousands of html & jpeg files Maria Sophia <mariasophia@comprehension.com> - 2026-07-05 15:23 -0600
  Re: How to copy & read a huge zipped book with thousands of html & jpeg files Arno Welzel <usenet@arnowelzel.de> - 2026-07-06 17:48 +0200

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