github.com/eloyucu/xml-stream-parser

xml stream parser

xml-stream-parser is xml parser for GO. It is efficient to parse large xml data with streaming fashion.

Usage

<?xml version="1.0" encoding="UTF-8"?>
<bookstore>
   <book isbn="AAA">
      <title>20 Love poems and a song of dispair</title>
      <price>12.95</price>
      <comments>
      </comments>
   </book>
   <book isbn="XXX">
      <title>The Iliad and The Odyssey</title>
      <price>12.95</price>
      <comments>
         <userComment rating="4">Best translation I've read.</userComment>
         <userComment rating="2">I like other versions better.</userComment>
      </comments>
   </book>
   <book isbn="YYY">
      <title>Anthology of World Literature</title>
      <price>24.95</price>
      <comments>
         <userComment rating="3">Needs more modern literature.</userComment>
         <userComment rating="4">Excellent overview of world literature.</userComment>
      </comments>
   </book>
</bookstore>

Stream over books

f, _ := os.Open("input.xml")
br := bufio.NewReaderSize(f,65536)
parser := xmlparser.NewXMLParser(br, "book")

for xml := range parser.Stream() {
	fmt.Println(xml.Childs["title"][0].InnerText)
	fmt.Println(xml.Childs["comments"][0].Childs["userComment"][0].Attrs["rating"])
	fmt.Println(xml.Childs["comments"][0].Childs["userComment"][0].InnerText)
}
   

Skip tags for speed

parser := xmlparser.NewXMLParser(br, "book").SkipElements([]string{"price", "comments"})

Error handlings

for xml := range parser.Stream() {
   if xml.Err !=nil { 
      // handle error
   }
}

Progress of parsing

// total byte read to calculate the progress of parsing
parser.TotalReadSize

Using GetValue function from a XMLElement instance:

value = xml.GetValue("comments.userComment")
value = xml.GetValue("comments[1].userComment[1]")

if you would want to get the InnerText from a node:

value = node.GetValue(".")

and never do GetValue(""). To get an attribute value:

attValue = xml.GetValue("comments[1].userComment@rating")
attValue = xml.GetValue("comments.userComment[1]@rating")
attValue = xml.GetValue("@isbn")

If the value of the nodes are numeric we can use functions which allow get them converted to the numeric values:

intValue = xml.GetValueInt("comments[1].userComment@rating")
intValue = xml.GetValueInt("comments.userComment[1]@rating")
float64Value = xml.GetValueF64("price")

These values will be 0 if the value of the node is not numeric.
There is an option to get the value of a node from a path diving in each node of that path until arrive to the goal, for example doing:

comment = bookstore.GetValueDeep("book.comments.userComment")

it will return Best translation I've read. because is the first instance which has the complete path. GetValueIntDeep and GetValueF64Deep are too valid. Using GetNodes and GetNode function from a XMLElement instance:

singleNode = xml.GetNode("comments.userComment")
singleNode = xml.GetNode("comments[1].userComment[1]")

and

nodeArray = xml.GetNodes("comments.userComment")
nodeArray = xml.GetNodes("comments[1].userComment")

Using GetAllNodes function from a XMLElement instance: This function allows to get all nodes following all the tree of the passed xpath and recovering all its leafs, for example

f, _ := os.Open("input.xml")
br := bufio.NewReaderSize(f,65536)
parser := xmlparser.NewXMLParser(br, "bookstore") 
// notice we are getting the root node, so the next for will loop only 1 time 
for xml := range parser.Stream() {
   nodes := xml.GetAllNodes("book.comment.userComment")
}

this invokation will return an array of 4 elements, 2 of each comments node.

If you interested check also json parser which works similarly