1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
"""
***************************************************************************
user.py
---------------------
Date : January 2015
Copyright : (C) 2015 by Nathan Woodrow
Email : woodrow dot nathan at gmail dot com
***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************
"""
__author__ = "Nathan Woodrow"
__date__ = "January 2015"
__copyright__ = "(C) 2015, Nathan Woodrow"
import os
import sys
import glob
import traceback
from qgis.PyQt.QtCore import QCoreApplication, qDebug
from qgis.core import Qgis, QgsApplication, QgsMessageLog
def load_user_expressions(path):
"""
Load all user expressions from the given paths
"""
# Loop all py files and import them
modules = glob.glob(path + "/*.py")
names = [os.path.basename(f)[:-3] for f in modules]
for name in names:
if name == "__init__":
continue
# As user expression functions should be registered with qgsfunction
# just importing the file is enough to get it to load the functions into QGIS
try:
__import__(f"expressions.{name}", locals(), globals())
except:
error = traceback.format_exc()
msgtitle = QCoreApplication.translate("UserExpressions", "User expressions")
msg = QCoreApplication.translate(
"UserExpressions", "The user expression {0} is not valid"
).format(name)
QgsMessageLog.logMessage(
msg + "\n" + error, msgtitle, Qgis.MessageLevel.Warning
)
def reload_user_expressions(path):
"""
Reload all user expressions from the given path
"""
# First unload expression modules, looping all
# py files and remove them from sys.modules
modules = glob.glob(path + "/*.py")
names = [os.path.basename(f)[:-3] for f in modules]
for name in names:
if name == "__init__":
continue
mod = f"expressions.{name}"
if mod not in sys.modules:
continue
# try removing path
if hasattr(sys.modules[mod], "__path__"):
for path in sys.modules[mod].__path__:
try:
sys.path.remove(path)
except ValueError:
# Discard if path is not there
pass
# try to remove the module from python
try:
del sys.modules[mod]
except:
qDebug("Error when removing module:\n%s" % traceback.format_exc())
# Finally, load again the users expressions from the given path
load_user_expressions(path)
userpythonhome = os.path.join(QgsApplication.qgisSettingsDirPath(), "python")
expressionspath = os.path.join(userpythonhome, "expressions")
sys.path.append(userpythonhome)
if not os.path.exists(expressionspath):
os.makedirs(expressionspath)
initfile = os.path.join(expressionspath, "__init__.py")
if not os.path.exists(initfile):
open(initfile, "w").close()
template = """from qgis.core import *
from qgis.gui import *
@qgsfunction(group='Custom', referenced_columns=[])
def my_sum(value1, value2):
\"\"\"
Calculates the sum of the two parameters value1 and value2.
<h2>Example usage:</h2>
<ul>
<li>my_sum(5, 8) -> 13</li>
<li>my_sum(\"field1\", \"field2\") -> 42</li>
</ul>
\"\"\"
return value1 + value2
"""
default_expression_template = template
try:
import expressions
expressions.load = load_user_expressions
expressions.load(expressionspath)
expressions.template = template
expressions.reload = reload_user_expressions
except ImportError:
# We get a import error and crash for some reason even if we make the expressions package
# TODO Fix the crash on first load with no expressions folder
# But for now it's not the end of the world if it doesn't load the first time
pass
|
