xmllint命令处理xml与html的例子
xmllint是一个很方便的处理及验证xml、处理html的工具,linux下只要安装libxml2就可以使用这个命令,首先看下其结合--html、--xpath参数处理html时的例子.
例子: curl http://www.phpfensi.com /ip/?q=8.8.8.8 2>/dev/null | xmllint --html --xpath "//ul[@id='csstb']" - 2>/dev/null | sed -e 's/<[^>]*>//g'
上例中主要是通过在123cha上查询的IP地址的归属情况后,通过提取结果（ul#csstb）,只获取文本部分的内容,上面的脚本语句执行后的结果如下:
[您的查询]:8.8.8.8 本站主数据: 美国 本站辅数据:Google Public DNS提供:hypo 美国 Google免费的Google Public DNS提供:zwstar参考数据一:美国 参考数据二:美国下面再结合示例看下其他主要参数的用法.
1、--format
此参数用于格式化xml,使其具有良好的可读性,假设有xml(person.xml)内容如下:
<person><name>ball</name><age>30</age<sex>male</sex></person>
执行如下操作后其输出为更易读的xml格式:
＃xmllint --format person.xml <? xml version = "1.0" ?> < person > < name > ball </ name > < age > 30 </ age > < sex > male </ sex > </ person >2、--noblanks
与--format相反,有时为了节省传输量,我们希望去掉xml中的空白,这时我们可以使用--noblanks命令.
假设xml(person.xml)内容如下:
<? xml version = "1.0" ?> < person > < name > ball </ name > < age > 30 </ age > < sex > male </ sex > </ person >执行该参数操作后,其输出结果为:
＃xmllint --noblanks person.xml <? xml version = "1.0" ?> < person > < name > ball </ name > < age > 30 </ age > < sex > male </ sex > </ person >3、--schema
使用scheam验证xml文件的正确性（XML Schema 是基于 XML 的 DTD 替代者）,假设有xml文件（person.xml）和scheam文件（person.xsd）文件,内容分别如下:
person.xml
<? xml version = "1.0" ?> < person > < name > ball </ name > < age > 30 </ age > < sex > male </ sex > </ person >person.xsd
<? xml version = "1.0" ?> < xs:schema xmlns:xs = "http://www.w3.org/2001/XMLSchema" > < xs:element name = "name" type = "xs:string" /> < xs:element name = "age" type = "xs:integer" /> < xs:element name = "sex" > < xs:simpleType > < xs:restriction base = "xs:string" > < xs:enumeration value = "male" /> < xs:enumeration value = "female" /> </ xs:restriction > </ xs:simpleType > </ xs:element > < xs:element name = "person" > < xs:complexType > < xs:all > < xs:element ref = "name" /> < xs:element ref = "age" /> < xs:element ref = "sex" /> </ xs:all > </ xs:complexType > </ xs:element > </ xs:schema >按如下命令执行后的结果是:
#xmllint --schema person.xsd person.xml <? xml version = "1.0" ?> < person > < name > ball </ name > < age > 30 </ age > < sex > male </ sex > </ person > person.xml validates注:默认情况下,验证后会输出验证的文件内容,可以使用 --noout选项去掉此输出,这样我们可以只得到最后的验证结果.
#xmllint --noout --schema person.xsd person.xml
person.xml validates
下面我们改动person.xml,使这份文件age字段和sex都是不符合xsd定义的.
＃xmllint --noout --schema person.xsd person.xml person.xml:4: element age: Schemas validity error : Element 'age': 'not age' is not a valid value of the atomic type 'xs:integer'. person.xml:5: element sex: Schemas validity error : Element 'sex': [facet 'enumeration'] The value 'test' is not an element of the set {'male', 'female'}. person.xml:5: element sex: Schemas validity error : Element 'sex': 'test' is not a valid value of the local atomic type. person.xml fails to validate可以看到xmllint成功的报出了错误.
4、关于--schema的输出
在讲输出之前先看下面一个场景,假如你想通过php执行xmllint然后拿到返回结果,你的代码通常应该是这个样子valid.php,实例代码如下:
$command = "xmllint --noout --schema person.xsd person.xml" ; exec ( $command , $output , $retval ); //出错时返回值不为0 if ( $retval != 0){ var_dump( $output ); } //开源代码phpfensi.com else { echo "yeah!" ; }我们保持上文中person.xml的错误。
执行此代码,你会发现,你拿到的output不是错误,而是array(0) {},amazing！
为什么会这样呢？
因为xmllint --schema,如果验证出错误,错误信息并不是通过标准输出（stdout）显示的,而是通过标准错误（stderr）进行显示的,而exec的output参数拿到的,只能是标准输出（stdout）显示的内容.
所以,为了拿到出错信息,我们需要将标准错误重定向到标准输出,对应修改代码:
$command = "xmllint --noout --schema person.xsd person.xml 2>$1";
再次执行valid.php,错误信息顺利拿到.
例子: 首先建立一份 xml 文档,命名为 po.xml,其内容如下:
<? xml version = "1.0" ?> < purchaseOrder orderDate = "1999-10-20" > < shipTo country = "US" > < name > Alice Smith </ name > < street > 123 Maple Street </ street > < city > Mill Valley </ city > < state > CA </ state > < zip > 90952 </ zip > </ shipTo > < billTo country = "US" > < name > Robert Smith </ name > < street > 8 Oak Avenue </ street > < city > Old Town </ city > < state > PA </ state > < zip > 95819 </ zip > </ billTo > < comment > Hurry, my lawn is going wild! </ comment > < items > < item partNum = "872-AA" > < productName > Lawnmower </ productName > < quantity > 1 </ quantity > < USPrice > 148.95 </ USPrice > < comment > Confirm this is electric </ comment > </ item > < item partNum = "926-AA" > < productName > Baby Monitor </ productName > < quantity > 1 </ quantity > < USPrice > 39.98 </ USPrice > < shipDate > 1999-05-21 </ shipDate > </ item > </ items > </ purchaseOrder >然后为 po.xml 写的 schema 文件,取名为 po.xsd,内容如下:
< xsd:schema xmlns:xsd = "http://www.w3.org/2001/XMLSchema" > < xsd:annotation > < xsd:documentation xml:lang = "en" > Purchase order schema for Example.com. Copyright 2000 Example.com. All rights reserved. </ xsd:documentation > </ xsd:annotation > < xsd:element name = "purchaseOrder" type = "PurchaseOrderType" /> < xsd:element name = "comment" type = "xsd:string" /> < xsd:complexType name = "PurchaseOrderType" > < xsd:sequence > < xsd:element name = "shipTo" type = "USAddress" /> < xsd:element name = "billTo" type = "USAddress" /> < xsd:element ref = "comment" minOccurs = "0" /> < xsd:element name = "items" type = "Items" /> </ xsd:sequence > < xsd:attribute name = "orderDate" type = "xsd:date" /> </ xsd:complexType > < xsd:complexType name = "USAddress" > < xsd:sequence > < xsd:element name = "name" type = "xsd:string" /> < xsd:element name = "street" type = "xsd:string" /> < xsd:element name = "city" type = "xsd:string" /> < xsd:element name = "state" type = "xsd:string" /> < xsd:element name = "zip" type = "xsd:decimal" /> </ xsd:sequence > < xsd:attribute name = "country" type = "xsd:NMTOKEN" fixed = "US" /> </ xsd:complexType > < xsd:complexType name = "Items" > < xsd:sequence > < xsd:element name = "item" minOccurs = "0" maxOccurs = "unbounded" > < xsd:complexType > < xsd:sequence > < xsd:element name = "productName" type = "xsd:string" /> < xsd:element name = "quantity" > < xsd:simpleType > < xsd:restriction base = "xsd:positiveInteger" > < xsd:maxExclusive value = "100" /> </ xsd:restriction > </ xsd:simpleType > </ xsd:element > < xsd:element name = "USPrice" type = "xsd:decimal" /> < xsd:element ref = "comment" minOccurs = "0" /> < xsd:element name = "shipDate" type = "xsd:date" minOccurs = "0" /> </ xsd:sequence > < xsd:attribute name = "partNum" type = "SKU" use = "required" /> </ xsd:complexType > </ xsd:element > </ xsd:sequence > </ xsd:complexType > <!-- Stock Keeping Unit, a code for identifying products --> < xsd:simpleType name = "SKU" > < xsd:restriction base = "xsd:string" > < xsd:pattern value = "d{3}-[A-Z]{2}" /> </ xsd:restriction > </ xsd:simpleType > </ xsd:schema >使用 xmllint 对 po.xml 文件进行校验:
$xmllint -schema po.xsd po.xml如果无出错信息,就说明校验通过了.
查看更多关于xmllint命令处理xml与html的例子 - php高级应用的详细内容...
声明：本文来自网络，不代表【好得很程序员自学网】立场，转载请注明出处：http://www.haodehen.cn/did30074