forked from clbanning/mxj
-
Notifications
You must be signed in to change notification settings - Fork 0
/
doc.go
138 lines (109 loc) · 7.83 KB
/
doc.go
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
133
134
135
136
137
138
// mxj - A collection of map[string]interface{} and associated XML and JSON utilities.
// Copyright 2012-2019, Charles Banning. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file
/*
Marshal/Unmarshal XML to/from map[string]interface{} values (and JSON); extract/modify values from maps by key or key-path, including wildcards.
mxj supplants the legacy x2j and j2x packages. The subpackage x2j-wrapper is provided to facilitate migrating from the x2j package. The x2j and j2x subpackages provide similar functionality of the old packages but are not function-name compatible with them.
Note: this library was designed for processing ad hoc anonymous messages. Bulk processing large data sets may be much more efficiently performed using the encoding/xml or encoding/json packages from Go's standard library directly.
Related Packages:
checkxml: github.com/clbanning/checkxml provides functions for validating XML data.
Notes:
2020.05.01: v2.2 - optimize map to XML encoding for large XML docs.
2019.07.04: v2.0 - remove unnecessary methods - mv.XmlWriterRaw, mv.XmlIndentWriterRaw - for Map and MapSeq.
2019.07.04: Add MapSeq type and move associated functions and methods from Map to MapSeq.
2019.01.21: DecodeSimpleValuesAsMap - decode to map[<tag>:map["#text":<value>]] rather than map[<tag>:<value>].
2018.04.18: mv.Xml/mv.XmlIndent encodes non-map[string]interface{} map values - map[string]string, map[int]uint, etc.
2018.03.29: mv.Gob/NewMapGob support gob encoding/decoding of Maps.
2018.03.26: Added mxj/x2j-wrapper sub-package for migrating from legacy x2j package.
2017.02.22: LeafNode paths can use ".N" syntax rather than "[N]" for list member indexing.
2017.02.21: github.com/clbanning/checkxml provides functions for validating XML data.
2017.02.10: SetFieldSeparator changes field separator for args in UpdateValuesForPath, ValuesFor... methods.
2017.02.06: Support XMPP stream processing - HandleXMPPStreamTag().
2016.11.07: Preserve name space prefix syntax in XmlSeq parser - NewMapXmlSeq(), etc.
2016.06.25: Support overriding default XML attribute prefix, "-", in Map keys - SetAttrPrefix().
2016.05.26: Support customization of xml.Decoder by exposing CustomDecoder variable.
2016.03.19: Escape invalid chars when encoding XML attribute and element values - XMLEscapeChars().
2016.03.02: By default decoding XML with float64 and bool value casting will not cast "NaN", "Inf", and "-Inf".
To cast them to float64, first set flag with CastNanInf(true).
2016.02.22: New mv.Root(), mv.Elements(), mv.Attributes methods let you examine XML document structure.
2016.02.16: Add CoerceKeysToLower() option to handle tags with mixed capitalization.
2016.02.12: Seek for first xml.StartElement token; only return error if io.EOF is reached first (handles BOM).
2015-12-02: NewMapXmlSeq() with mv.XmlSeq() & co. will try to preserve structure of XML doc when re-encoding.
2014-08-02: AnyXml() and AnyXmlIndent() will try to marshal arbitrary values to XML.
SUMMARY
type Map map[string]interface{}
Create a Map value, 'mv', from any map[string]interface{} value, 'v':
mv := Map(v)
Unmarshal / marshal XML as a Map value, 'mv':
mv, err := NewMapXml(xmlValue) // unmarshal
xmlValue, err := mv.Xml() // marshal
Unmarshal XML from an io.Reader as a Map value, 'mv':
mv, err := NewMapXmlReader(xmlReader) // repeated calls, as with an os.File Reader, will process stream
mv, raw, err := NewMapXmlReaderRaw(xmlReader) // 'raw' is the raw XML that was decoded
Marshal Map value, 'mv', to an XML Writer (io.Writer):
err := mv.XmlWriter(xmlWriter)
raw, err := mv.XmlWriterRaw(xmlWriter) // 'raw' is the raw XML that was written on xmlWriter
Also, for prettified output:
xmlValue, err := mv.XmlIndent(prefix, indent, ...)
err := mv.XmlIndentWriter(xmlWriter, prefix, indent, ...)
raw, err := mv.XmlIndentWriterRaw(xmlWriter, prefix, indent, ...)
Bulk process XML with error handling (note: handlers must return a boolean value):
err := HandleXmlReader(xmlReader, mapHandler(Map), errHandler(error))
err := HandleXmlReaderRaw(xmlReader, mapHandler(Map, []byte), errHandler(error, []byte))
Converting XML to JSON: see Examples for NewMapXml and HandleXmlReader.
There are comparable functions and methods for JSON processing.
Arbitrary structure values can be decoded to / encoded from Map values:
mv, err := NewMapStruct(structVal)
err := mv.Struct(structPointer)
To work with XML tag values, JSON or Map key values or structure field values, decode the XML, JSON
or structure to a Map value, 'mv', or cast a map[string]interface{} value to a Map value, 'mv', then:
paths := mv.PathsForKey(key)
path := mv.PathForKeyShortest(key)
values, err := mv.ValuesForKey(key, subkeys)
values, err := mv.ValuesForPath(path, subkeys) // 'path' can be dot-notation with wildcards and indexed arrays.
count, err := mv.UpdateValuesForPath(newVal, path, subkeys)
Get everything at once, irrespective of path depth:
leafnodes := mv.LeafNodes()
leafvalues := mv.LeafValues()
A new Map with whatever keys are desired can be created from the current Map and then encoded in XML
or JSON. (Note: keys can use dot-notation. 'oldKey' can also use wildcards and indexed arrays.)
newMap, err := mv.NewMap("oldKey_1:newKey_1", "oldKey_2:newKey_2", ..., "oldKey_N:newKey_N")
newMap, err := mv.NewMap("oldKey1", "oldKey3", "oldKey5") // a subset of 'mv'; see "examples/partial.go"
newXml, err := newMap.Xml() // for example
newJson, err := newMap.Json() // ditto
XML PARSING CONVENTIONS
Using NewMapXml()
- Attributes are parsed to `map[string]interface{}` values by prefixing a hyphen, `-`,
to the attribute label. (Unless overridden by `PrependAttrWithHyphen(false)` or
`SetAttrPrefix()`.)
- If the element is a simple element and has attributes, the element value
is given the key `#text` for its `map[string]interface{}` representation. (See
the 'atomFeedString.xml' test data, below.)
- XML comments, directives, and process instructions are ignored.
- If CoerceKeysToLower() has been called, then the resultant keys will be lower case.
Using NewMapXmlSeq()
- Attributes are parsed to `map["#attr"]map[<attr_label>]map[string]interface{}`values
where the `<attr_label>` value has "#text" and "#seq" keys - the "#text" key holds the
value for `<attr_label>`.
- All elements, except for the root, have a "#seq" key.
- Comments, directives, and process instructions are unmarshalled into the Map using the
keys "#comment", "#directive", and "#procinst", respectively. (See documentation for more
specifics.)
- Name space syntax is preserved:
- <ns:key>something</ns.key> parses to map["ns:key"]interface{}{"something"}
- xmlns:ns="http://myns.com/ns" parses to map["xmlns:ns"]interface{}{"http://myns.com/ns"}
Both
- By default, "Nan", "Inf", and "-Inf" values are not cast to float64. If you want them
to be cast, set a flag to cast them using CastNanInf(true).
XML ENCODING CONVENTIONS
- 'nil' Map values, which may represent 'null' JSON values, are encoded as "<tag/>".
NOTE: the operation is not symmetric as "<tag/>" elements are decoded as 'tag:""' Map values,
which, then, encode in JSON as '"tag":""' values..
- ALSO: there is no guarantee that the encoded XML doc will be the same as the decoded one. (Go
randomizes the walk through map[string]interface{} values.) If you plan to re-encode the
Map value to XML and want the same sequencing of elements look at NewMapXmlSeq() and
mv.XmlSeq() - these try to preserve the element sequencing but with added complexity when
working with the Map representation.
*/
package mxj