Re: where are incoming text photographs stored?

Jeff Layman wrote on Sat, 29 Jun 2024 22:01:58 +0100 :

Firstly, there might be some differences in using PulseSMS and using the
built-in Google message app, simply because the first is a downloaded
app and the second is a system app. The directories used and access
limitations seem to be the same, though (see next paragraph). There
might also be differences in how "stock" android and the Xiaomi version
behave.

Hi Jeff,
Always a pleasure conversing with you as we each add value to the other,
and others can benefit from what we ascertain from learned from each other.

I think the fundamental apps (e.g., messaging & contact & phone & keyboard)
all use the same "database" no matter what app we use to access that db.

An example is that the Android "contacts" are stored in a specific sqlite
contacts database, such that every contacts app accesses the same files.

Same with messaging apps (as far as I'm aware, anyway).

Remember, I tested every free Android messaging app long ago, and they each
only worked if I set them as the default - and then they took a few minutes
to absorb the database - because there is only one real messaging database.

My point is the actual contacts are stored in Android in the same place no
matter which contacts app you use - but - some contacts apps (such as the
ones that I use) do *extra* stuff with that database (which is the data
that is part of the contacts app which is in the protected file system).

Same I think with messaging apps.

You can have only one default messaging app at a time - but you can change
them - and they will read (after a few minutes of activity) the same
messages.

Then, on top of that, you can "add stuff", where, for example, in PulseSMS,
I can give a chat or contact a particular color or I can give them a
particular name (which is independent of the contact name for example).

That "extra" information is what I think is stored in the data directory of
the app that you and I know where it is but we are not rooted so we can't
see it due to the permissions problems of not having root access to it.

Here's an example which seems to back up my assumption above:
1. I load a new messaging app - which sees all my messages
2. I switch to PulseSMS - which also sees all my messages
3. But then I "add stuff" to those messages (like names & colors)
4. When I switch back to the original messaging app - all the stuff
   I added in PulseSMS is now gone.

This tells me three things:
a. The messages are stored somewhere centrally in Android
b. Every messaging app can access those messages
c. But if you add "stuff" with the messaging app, that stuff is
   stored locally to the messaging app (likely in protected storage)

I could be wrong though... but I'm an extremely empirical person, so much
of what I know is from experience because I'm not afraid to test things.

The "Files" app mentioned in the Ghisler Total Commander webpage
is the Google one, but MAM informs me that "Files" on my phone is a
Xiaomi app.

Bear in mind the name that shows up on the icon is not unique.
The package name is unique though. As is the package & version number.

For example, in MAM, I typed "File" & up came more than a half dozen apps:
 File Manager <pl.mkexplorer.kormateusz>
 File Manager <com.simplemobiletools.filemanager.pro>
 Files <com.google.android.documentsui>
 Files <org.aospstudio.files>
 Material Files <me.zhanghai.android.files>
 My Files <com.sec.android.app.myfiles>
 OI File Manager <org.openintents.filemanager>
 
And that doesn't even count half of my file managers, the rest of which
don't have the word "file" in the app name or in the package name.

However, when Total Commander tells me it can't access the
/data/user/0/ directory, it offers access via the Files app. If I allow
that, the Files app (I assume the Xiaomi one) says there is nothing in
that directory!

Yes. +1. Exactly. It's not that there is nothing in /data/user/0,
but that we don't have root access to that protected directory.

I want to be very clear that there are two kinds of "file managers" out
there, since I tested every free one that was suggested on this newsgroup.

One kind, like Total Commander & like ZArchiver & MixPlorer, will actually
let you see into the /data/user/0 directory; but most of the file managers
won't even let you see into the /data directory.

How deeply a file manager can go depends both on the file manager, and,
eventually, on whether or not you have root access (which we don't).

I guess this accords with your comment about PulseSMS
using /storage/emulated/0/Pictures/Pulse/.

Yes. The funny thing about some apps is they sometimes tell you WHERE they
store stuff that you can access, and they sometimes do not tell you.

For PulseSMS, they don't tell you WHERE they store the MMS media.
They only give you the option to "automatically" store the MMS media.

You can always longpress on any MMS media in PulseSMS and it will ask you
if you want to share or save or delete that MMS media; but it doesn't say
*where* it puts that MMS media when you save it.

You just have to look around for where it saves it.

Other apps will ask you where you want to store the media, where some apps,
like many camera apps, only give you the choice of internal or external
memory.

Other apps give you the choice of the exact folder on the internal or
external memory.

Only some apps tell you WHERE they put the stuff you can access.
Most do not.

You have to look around. :(

Unfortunately, if I look at
/storage/emulated/0/Pictures/Messages/ it is empty, and I know that at
least one picture sent with a message some time ago should be there if
that's where Messages stores its "attached" pictures. I still haven't
found where that picture is stored.

Hmmm... you have the *folder*, right? So that's a good hint.
I wonder what happens if you longpress on an image that came in through
MMS, and let the messaging app save that image manually.

Does it go there then?

For example, I use a lot of the cartoonify apps, which all seem to store
their results in the  /storage/emulated/0/Pictures/<nameofcartoonapp> dir.

But they don't store anything in that directory until I tell them to save.
Check out if Messages is doing that for you.

I must say that I get very confused about message apps storage. MAM
informs me there are two apps with "message" in the name.

+1. It's confusing. Which is why the "name" isn't what is unique.
Only the package name is unique.

For example, I also have multiple apps with "messages" in the name.
 Messages <com.samsung.android.messaging>
 Messages <com.messages.chat>

You need the full unique package name to distinguish between them.
The fact that you need the full package name is where MAM comes into play.
Most app managers truncate the name but MAM always give you the full name.

The first is
simply called "Messages" (com.google.android.apps.messaging). The Data
Directory and Device-protected Data Directory are as you found above -
/data/user/0/ and /data/user-de/0/. The second is Phone and Messaging
Storage (com.android.providers.telephony). This uses the same Data
Directory and Device-protected Data Directory as mentioned above.
According to MAM, Data usage for both of these apps is 0B! Yet I have
quite a few messages stored, one with a picture. So why is the data
usage 0B? It's even more confusing because "Settings" | Message App info
tells me that Storage is 0B, but data usage for the Message app is
27.7MB! For the Phone and Messaging Storage app both Storage and Data
usage are 0B.

Hmmm... I do not know about this.... let me look at mine in MAM...

1. When I look in MAM at PulseSMS <xyz.klinker.messenger>
2. Under MAM "Storage & Cache" for <xyz.klinker.messenger> is
   a. App 35.80MB
   b. Data 1.81GB
   c. Cache 4.10kB
   d. Total 1.84GB
3. If I then click in MAM "View in Settings" for <xyz.klinker.messenger>
   it brings me to the Android settings for that specific app. saying:
    Storage 1.84GB used in internal storage
     a. App 35.80MB
     b. Data 1.81GB
     c. Cache 4.10kB
     d. Total 1.84GB

Which, at the bottom, allows me to "Clear Data" or "Clear Cache" if I want.
I am afraid to hit those two buttons, but at least my numbers jibe well.

Both "Messages" and "Phone and Messaging Storage" have a permission set
for "SMS", so are both used when SMS are sent/received?

When I tested all the free adfree Android messaging apps, I came to the
empirical conclusion only one default messenger is allowed to be active.

But I will leave the answer to how "Messages" differs from "Phone and
Messaging Storage" to someone who knows more about this stuff than I do.

Just one final point. MAM finds no app with "sms" in the name, but
searching for "mms" it finds MmsService (com.android.mms.service).

When I search in MAM for "sms" I get the following, which are different:
 Dsms <com.samsung.android.dsms>
 GPS to SMS <ru.perm.trubnikov.gps2sms>
 Sec Media Storage <com.samsung.android.providers.media>
 SMS Import / Export <com.github.tmo1.sms_ie>
 SMS Messenger <com.simplemobiletools.smsmessenger>
 SOS Alert <com.main.contacts.smsmanager>

For a search in MAM for "mms", I only get this one package:
 MmsService <com.android.mms.service>

But, of course, this is dependent mostly on what you've installed prior.

This
app also shows as having 0B for Storage and Data usage, and the only
permission allowed is SMS.

My MmsService <com.android.mms.service> package shows in MAM the following:
 Source Directory /system/priv-app/MmsService
 Data Directory /data/user/0/com.android.mms.service
 Device-protected Data Directory /data/user_de/0/com.android.mms.service
 Storage and Cache
  App 229kB
  Data 18.43kB
  Cache 14.34kB
  Total 262kB

I thought that an attached picture would use
MMS. Is that not correct?

Well, what you're running into here is part of the complexity of any
operating system, where there are user-facing apps (such as a web browser,
or a contact manager or a sms/mms messenger, etc.) and all the underlying
services that are involved in the entire process.

To oversimplify what I said above, there are two kinds of packages:
a. Those packages which are apps you (or your carrier) installed, and,
b. Those packages which are necessary (or not) for Android to work.

Most of the bloat, by the way, are packages which are NOT necessary for
Android to work (such as, oh, Android System, despite the ominous name!).
 Android System <com.google.android.adservices.api>

Another package that is not necessary even though it sounds important is
 Device Health Services <com.google.android.apps.turbo>

How do I know this? I've long ago disabled scores & my phone is fine.
 Private Compute Services <com.google.android.as.oss>

Hope this reply makes some sense... :-)

Almost everything you saw is what I've seen in the past, so most of it made
sense, although some of it I don't understand.

That's where the others who know more than we do can help us out.
Most of what I know is purely empirical; I test things out.

I'm glad you're testing things out also as most people don't bother.