TDynamicDLL improvements and other fixes

[idanmiara]

No description provided.

[pyscripter]

I am not sure what it the problem you are trying to solve. From what I see you set the RegVersion from aDLLName in TPythonEngine.DoOpenDll(const aDllName : String) if UseLastKnownerion is False.
What is the use of that?

PyhthonEngine can be used to work with (a) a registered Python version and (b) a non registered Python version.

In (a) you need to set

• RegVersion, DLLName and optionally UseLastKnownVersion if a version newer than RegVersion will do.

In (b) you need to :

• Set DDLPath, RegVersion, DLLName and set UseLastKnownVersion to false.
• Call SetPythonHome to the appropriate path or set the %PYTHONHOME% environment variable.

[pyscripter]

Also the implementation GetPythonVersionFromDLLName is platform specific (Windows). In addition there is no need for it to be a member of PythonEngine. It could be a stand-alone function (possibly inside PythonVersions), or a class function.

[idanmiara]

Hi, Thanks for your prompt response. The problem I'm trying to solve is as follows: UserInputDllName := ''; // allow user to input UserInputDllName if he wishes. PyEngine.DllName := UserInputDllName; PyEngine.UseLastKnownVersion := PyEngine.DllName=''; now I want to read PyEngine.RegVersion and I will get a wrong answer in case the user specified the DLL name. I made it platform independent as you suggested. Please note that I GetPythonVersionFromDLLName is a stand alone function and not a method. I put it in PythonEngine.pas and not elsewhere because I use it in PythonEngine.pas and PythonEngine.pas dosen't use any other p4d unit. I didn't see the justification to add a dependency or make a new unit for this function. I'm also pushing my version of LatestPythonVersionFromPath which as far as I can tell is platform independent unlike to PythonVersionFromPath and also allow the use of the uncommon setup of OSGeo4W.

…

On Thu, 25 Oct 2018 at 04:15, pyscripter ***@***.***> wrote: Also the implementation GetPythonVersionFromDLLName is platform specific (Windows). In addition there is no need for it to be a member of PythonEngine. It could be a stand-alone function (possibly inside PythonVersions), or a class function. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#62 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AZIQrc1vM2HmQQFmGS_NCUmf_S0WSlI_ks5uoRDGgaJpZM4X4OaN> .

[pyscripter]

I am considering including GetPythonVersionFromDLLName and possibly LatestPythonVersionFromPath but I still do not see the purpose of your other changes:

What is the use of changing DoOpenDLL? You say that

The problem I'm trying to solve is as follows:
UserInputDllName := '';
// allow user to input UserInputDllName if he wishes.
PyEngine.DllName := UserInputDllName;
PyEngine.UseLastKnownVersion := PyEngine.DllName='';
now I want to read PyEngine.RegVersion and I will get a wrong answer in
case the user specified the DLL name.

Why don't you call GetPythonVersionFromDLLName in your code i.e

if UserInputDLLName <> '' then
  PythonEngine.RegVersion := GetPythonVersionFromDLLName(UserInputDLLName);

Also regarding LatestPythonVersionFromPath. This actually deals with a corner case and anyway enen after using this method you still have to call SetPythonHome with a different path than the DLLPath.
The simple solution for QGIS would be to copy the dll and python exe files to the python directory,
By the way a QGIS user of PyScripter suggested the following script for running QGIS with PyScripter (which uses P4D) after copying the dll and python.exe files.

call "%OSGEO4W_ROOT%\bin\o4w_env.bat"
call qt5_env.bat
call py3_env.bat

path %OSGEO4W_ROOT%\apps\qgis\bin;%PATH%
set QGIS_PREFIX_PATH=%OSGEO4W_ROOT:\=/%/apps/qgis
set GDAL_FILENAME_IS_UTF8=YES
rem Set VSI cache to be used as buffer, see #6448
set VSI_CACHE=TRUE
set VSI_CACHE_SIZE=1000000
set QT_PLUGIN_PATH=%OSGEO4W_ROOT%\apps\qgis\qtplugins;%OSGEO4W_ROOT%\apps\qt5\plugins
set PYTHONPATH=%OSGEO4W_ROOT%\apps\qgis\python;%PYTHONPATH%
start "PyScripter" %~pd0\PyScripter.exe --PYTHON36 --pythondllpath=%OSGEO4W_ROOT%\apps\python36

[idanmiara]

Hi, RE: Why don't you call GetPythonVersionFromDLLName in your code: I could do that. but I think that if you provide a property it should be valid for reading the state of the dll that was loaded. I didn't say It's a major bug, just a small fix. RE: LatestPythonVersionFromPath, I agree it's a corner case, but it's also platform independent and it's doesn't affect the normal use case (it would give the same result as the original function), so I don't see a reason not to add it. I do need to call SetPythonHome with a modified path, but I don't see your point about that. RE: PyScripter, I didn't know that program, I'll have a look, thanks :) RE: Batch file: I know that method and sometimes use it (i.e. before I used SetPythonHome and for using QGIS python with a different IDE), but I'm trying to make my app run without a wrapping batch file. I'm not sure about the reasons that QGIS/OSGeo4W chose this uncommon setup, but it's less likely to change soon...

…

On Thu, 25 Oct 2018 at 18:25, pyscripter ***@***.***> wrote: I am considering including GetPythonVersionFromDLLName and possibly LatestPythonVersionFromPath but I still do not see the purpose of your other changes: What is the use of changing DoOpenDLL? You say that The problem I'm trying to solve is as follows: UserInputDllName := ''; // allow user to input UserInputDllName if he wishes. PyEngine.DllName := UserInputDllName; PyEngine.UseLastKnownVersion := PyEngine.DllName=''; now I want to read PyEngine.RegVersion and I will get a wrong answer in case the user specified the DLL name. Why don't you call GetPythonVersionFromDLLName in your code i.e if UserInputDLLName <> '' then PythonEngine.RegVersion := GetPythonVersionFromDLLName(UserInputDLLName); Also regarding LatestPythonVersionFromPath. This actually deals with a corner case and anyway enen after using this method you still have to call SetPythonHome with a different path than the DLLPath. The simple solution for QGIS would be to copy the dll and python exe files to the python directory, By the way a QGIS user of PyScripter suggested the following script for running QGIS with PyScripter (which uses P4D) after copying the dll and python.exe files. call "%OSGEO4W_ROOT%\bin\o4w_env.bat" call qt5_env.bat call py3_env.bat path %OSGEO4W_ROOT%\apps\qgis\bin;%PATH% set QGIS_PREFIX_PATH=%OSGEO4W_ROOT:\=/%/apps/qgis set GDAL_FILENAME_IS_UTF8=YES rem Set VSI cache to be used as buffer, see #6448 set VSI_CACHE=TRUE set VSI_CACHE_SIZE=1000000 set QT_PLUGIN_PATH=%OSGEO4W_ROOT%\apps\qgis\qtplugins;%OSGEO4W_ROOT%\apps\qt5\plugins set PYTHONPATH=%OSGEO4W_ROOT%\apps\qgis\python;%PYTHONPATH% start "PyScripter" %~pd0\PyScripter.exe --PYTHON36 --pythondllpath=%OSGEO4W_ROOT%\apps\python36 — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#62 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AZIQrQmUNAqKu-DbKXBB3WZWInXADkGOks5uodfPgaJpZM4X4OaN> .

[idanmiara]

Hi,
I've rebased my changes on your master.
I'm using your TDynamicDll as a base for other dlls that I use.
I pushed some additions and fixes.
Should I keep posting improvements to this library? If you are willing to accept contributions I will keep post them.

[pyscripter]

The scope of the PR is becoming too wide, including different changes for different purposes. I am closing this. You are welcome to submit different PRs with narrow scope and specific purpose.