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1
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""" |
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2
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Usefull method and classes not belonging anywhere and depending on opcua library |
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3
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""" |
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4
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5
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from dateutil import parser |
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6
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from datetime import datetime |
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7
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from enum import Enum |
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8
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9
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from opcua import ua |
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10
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11
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12
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def val_to_string(val): |
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13
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""" |
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14
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convert a python object or python-opcua object to a string |
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15
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which should be easy to understand for human |
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16
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easy to modify, and not too hard to parse back ....not easy |
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17
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meant for UI or command lines |
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18
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19
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""" |
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20
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if isinstance(val, (list, tuple)): |
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21
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res = [] |
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22
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for v in val: |
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23
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res.append(val_to_string(v)) |
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24
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return "[" + ", ".join(res) + "]" |
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25
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26
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if isinstance(val, (ua.NodeId)): |
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27
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val = val.to_string() |
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28
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elif isinstance(val, (ua.QualifiedName, ua.LocalizedText)): |
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29
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val = val.to_string() |
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30
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elif isinstance(val, Enum): |
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31
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val = val.name |
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32
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elif isinstance(val, ua.DataValue): |
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33
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val = variant_to_string(val.Value) |
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34
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elif isinstance(val, str): |
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35
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pass |
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36
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elif isinstance(val, bytes): |
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37
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pass |
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38
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elif isinstance(val, datetime): |
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39
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val = val.isoformat() |
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40
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else: |
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41
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val = str(val) |
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42
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return val |
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43
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44
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45
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def variant_to_string(var): |
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46
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""" |
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47
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convert a variant to a string which should be easy to understand for human |
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48
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easy to modify, and not too hard to parse back ....not easy |
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49
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meant for UI or command lines |
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50
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""" |
|
51
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return val_to_string(var.Value) |
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52
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53
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54
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def string_to_val(string, vtype): |
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55
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""" |
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56
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Convert back a string to a python or python-opcua object |
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57
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""" |
|
58
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string = string.strip() |
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59
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if string.startswith("["): |
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60
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string = string[1:-1] |
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61
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var = [] |
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62
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for s in string.split(","): |
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63
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s = s.strip() |
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64
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val = string_to_val(s, vtype) |
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65
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var.append(val) |
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66
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return var |
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67
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68
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if vtype == ua.VariantType.Boolean: |
|
69
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val = bool(string) |
|
70
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elif 4 <= vtype.value < 9: |
|
71
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val = int(string) |
|
72
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elif vtype in (ua.VariantType.Float, ua.VariantType.Double): |
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73
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val = float(string) |
|
74
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elif vtype == ua.VariantType.String: |
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75
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val = string |
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76
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elif vtype == ua.VariantType.NodeId: |
|
77
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val = ua.NodeId.from_string(string) |
|
78
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elif vtype == ua.VariantType.DateTime: |
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79
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val = parser.parse(string) |
|
80
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else: |
|
81
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raise NotImplementedError |
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82
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return val |
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83
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|
84
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|
85
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def string_to_variant(string, vtype): |
|
86
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""" |
|
87
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convert back a string to an ua.Variant |
|
88
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""" |
|
89
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return ua.Variant(string_to_val(string, vtype), vtype) |
|
90
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91
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92
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FreeOpcUa /
python-opcua
