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Thu, 10 Feb 2022 17:43:10 +0100

adminsforum@hubzilla.org

KlausR schrieb den folgenden Beitrag Thu, 10 Feb 2022 17:43:08 +0100

Creation of a Clone by Exporting and Importing the json File

I tried to create a clone by using the channel export app and a subsequent import of the json file on another hub.
The export of the json file worked without any problems. However the import using the "Channel Import" form did not work - after clicking "Submit" I was again directed to the "Create a Channel" page without importing the file.
I entered a different nickname in the corresponding field of the form, as I want to use a different nickname on the clone hub.
I tried to import the json file on different hubs without success.
In the past I did never have any problems with this approach.
Is there a known/open issue concerning the import of json files for channel cloning?

show all 9 comments

Mon, 14 Feb 2022 16:54:25 +0100

KlausR

claus@hub.cloudlet.at

I checked the log file, which reports the following:

[14-Feb-2022 16:28:35 Europe/Vienna] PHP Warning:  Invalid argument supplied for foreach() in .../www/hubzilla/include/text.php on line 2651

In line 2651 of the text.php the following foreach function is included:

function stringify_array_elms(&$arr, $escape = false) {
        foreach($arr as $k => $v)
                $arr[$k] = "'" . (($escape) ? dbesc($v) : $v) . "'";
}

Does anybody have an idea, why an invalid argument is supplied for this foreach function?
I assume that this is somehow the reason, why I am not able to import the json file for channel cloning.

Mon, 14 Feb 2022 22:46:52 +0100

Malendur

malendur8944@hub.art3mis.de

Good catch.
Hopefully it will fix https://framagit.org/hubzilla/core/-/issues/1654 too.

Tue, 15 Feb 2022 10:54:09 +0100

Mario Vavti

mario@hub.somaton.com

@KlausR just did a brief test and had no issue importing the export json file at another hub.
We will need more info to find out what is going on in your case. The hubzilla logs of the import action would be helpful...

Tue, 15 Feb 2022 16:22:43 +0100

emaxmax

emaxmax@hub.netzgemeinde.eu

@KlausR
Add, just before the foreach :

if (!$arr || !is_array($arr )) {
print_r($arr);
}

It should print the invalid data.

Wed, 16 Feb 2022 22:21:04 +0100

KlausR

claus@hub.cloudlet.at

In my case I imported my channel on my hub some months ago - this way I created a clone with a certain nickname. A few days ago I deleted this clone and subsequently I wanted to import the channel a second time, however with a different nickname.
It seems as if a channel cannot be imported to a hub a second time due to security reasons, in order to avoid that the identity is captured by somebody else.
However, I do not fully understand the rationale. Why is it not possible to import a channel to the same hub a second time or even several times, however with different nicknames? This way the clones are anyway registered on the hub with different channel addresses and different channel structures, aren't they?
Would it be possible to permit the creation of several clones on the same hub using different nicknames, without violating the security aspect?

Wed, 16 Feb 2022 22:55:01 +0100

Mario Vavti

mario@hub.somaton.com

The nickname or channel address is not the primary ID for Hubzilla. It is basicall only used to communicate with other networks and for readability by humans. The primary ID is what we refer to as the xchan_hash. All your clones have the same xchan_hash no matter the nickname or hostname. This is actually what allows us to be nomadic.

Thu, 17 Feb 2022 23:50:32 +0100

Einer von Vielen

einer@digitalesparadies.de

But every clone (of a same) id has the same xchan_hash on each clone? Do I remember this correctly?

Fri, 18 Feb 2022 01:10:59 +0100

Einer von Vielen

einer@digitalesparadies.de

Some more words on this because by accident I talked about identities of Hubzilla/Zap/... and some basic concepts with @RockyIII (RockyIII) today. Please correct me anybody if I am wrong...

You can have a look at the exports of two clones.... settings > export channel /uexport

The "channel_guid" (and "channel_hash of course) is the same for each clone as well as the "channel_pubkey" and "channel_prvkey" The key stuff is used to technically prove your "channel_guid" (digitally sign it or end-to-end encrypt data). So you should never give the "channel_prvkey" away. Or in other words this is the part where you have to trust the owner of the server. This is a another reason to have your server (the hardware) at home. (If this can be save is another discussion ;-) )

Basically these values make your identity that you carry around as far as I know. The same principle (using a global unique id) applies to a file (for example) that has the same global unique id on each clone if you look into the database. To stay with the file example... Each file has stored the permission who can read/write it. (A permission is basically a list of id's) If you export/import or sync such a file the permissions are exported/imported or synced as well because the permissions are "glued" to the file.

Another cool stuff is if you implement an addon... There are always objects like an "observer" that holds the information, who is requesting (a file for example). And because you always know who is requesting this file or anything else (posts, webpages,...) you can easily check the permission because this is glued to every file (post,...). There are built-in functions for this. Complicated stuff is made easy for the programmer of an addon. The programmer has not to deal with it. Now think about clones and the synchronizations of files (post,...) This is a little bit more effort to have this kind of MAGIC but basically it is built-in. This should be a good motivation to implement addons for programmers.

Sorry for hijacking this thread. I think this is a good occasion to talk about some basic ideas and unique selling points of Hubzilla, ZAP,...

Fri, 18 Feb 2022 13:24:21 +0100

KlausR

claus@hub.cloudlet.at

@Einer von Vielen
Thank you for your detailed explanations, which make the identity and permission aspects clearer to me.
I agree that the cloning of channels is an excellent feature and a unique selling point of Hubzilla/ZAP ...
You can take your identity and wander around from hub to hub.
However, what I learned from this thread is that, if you completely leave a hub by deleting the identity from this hub, you can never come back again to this hub at a later point in time.
But I don't think that this is a problem, as long as you are aware of this behaviour.
Again, the principle of the nomadic identity is awesome!