[fpc-pascal] Problems with Postgresql Character Encoding

LacaK lacak at zoznam.sk
Wed Sep 26 11:30:58 CEST 2012

Mark Morgan Lloyd  wrote / napĂ­sal(a):
> Andrew Brunner wrote:
>> My cloud file/folder sync client desktop app builds and maintains a 
>> manifest of all files and folders from a specified starting point. I 
>> use this manifest to synchronize disk entries across devices.  It 
>> uses HTTP requests and XML to carry out all transactions.  Meaning 
>> there is no TSQLConnection.  The problem is that the HTTP server 
>> receives the data as XML and refuses to post changes.  If data (in 
>> updates or inserts) contains non-supported UTF8 characters postgresql 
>> rejects with character encoding notices.
>> I've tried with using AnsiToUTF8 and UTF8toAnsi.  That works for 
>> email messages.  However, since sync code has to scan tens of 
>> thousands of disk files/folders I don't think it's good for battery 
>> and memory consumption for a background app to consume cpu resources 
>> in this case going between 2 forms of the same file/folder name.
>> I need to be able to take advantage of Postgresql's client encoding 
>> method.  I know postgresql allows me to tell the server that the 
>> connection is presently character set "LATIN1".  And presumably 
>> postgresql server will convert what it needs to my database encoding 
>> of UTF8.
>> <snip>
>> SystemP^.Connection.Charset:='LATIN1';
>> This does nothing for me when Connection is a postgresql connection.
>> Anyone have any experience with postgresql character sets / encoding???
> No, but I'm interested since this is something that I anticipate 
> having to do.
> You might need to issue an explicit instruction to the PostgreSQL 
> server telling it to assume that the current session is encoded as 
> /whatever/. If you have to do that then you might find yourself having 
> to use the PQConnection's (or whatever the correct name is) low-level 
> handle, since working from memory the .Exec method uses a temporary 
> handle so any state change isn't retained. I had to delve into this 
> when getting listen/notify running reliably.
Do you have tried SQL:  SET CLIENT_ENCODING TO 'LATIN1' ?
May be that better would be add support for PQsetClientEncoding into 
TPQConnection ... I can look at it if you want.

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