为什么通过 XSD 进行的 XML 验证在 libxml2 中失败(但在 xmllint 中成功)以及如何修复它?
如果我通过 xmllint: 运行此 XML 验证:
xmllint --noout --schema schema.xsd test.xml
我会收到此成功消息:
.../test.xml validates
但是,如果我运行相同的验证通过libxml2的C API:
int result = xmlSchemaValidateDoc(...)
我得到返回值1845
和这个失败消息:
Element '{http://example.com/XMLSchema/1.0}foo': No matching global declaration available for the validation root.
我绝对可以做到没有感觉。 :(
schema.xsd:
<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE xs:schema PUBLIC "-//W3C//DTD XMLSCHEMA 200102//EN" "XMLSchema.dtd" >
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="http://example.com/XMLSchema/1.0" targetNamespace="http://example.com/XMLSchema/1.0" elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:element name="foo">
</xs:element>
</xs:schema>
test.xml:
<?xml version="1.0" encoding="UTF-8"?>
<foo xmlns="http://example.com/XMLSchema/1.0">
</foo>
main.c:
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <string.h>
#include <libxml/parser.h>
#include <libxml/valid.h>
#include <libxml/xmlschemas.h>
u_int32_t get_file_size(const char *file_name) {
struct stat buf;
if ( stat(file_name, &buf) != 0 ) return(0);
return (unsigned int)buf.st_size;
}
void handleValidationError(void *ctx, const char *format, ...) {
char *errMsg;
va_list args;
va_start(args, format);
vasprintf(&errMsg, format, args);
va_end(args);
fprintf(stderr, "Validation Error: %s", errMsg);
free(errMsg);
}
int main (int argc, const char * argv[]) {
const char *xsdPath = argv[1];
const char *xmlPath = argv[2];
printf("\n");
printf("XSD File: %s\n", xsdPath);
printf("XML File: %s\n", xmlPath);
int xmlLength = get_file_size(xmlPath);
char *xmlSource = (char *)malloc(sizeof(char) * xmlLength);
FILE *p = fopen(xmlPath, "r");
char c;
unsigned int i = 0;
while ((c = fgetc(p)) != EOF) {
xmlSource[i++] = c;
}
printf("\n");
printf("XML Source:\n\n%s\n", xmlSource);
fclose(p);
printf("\n");
int result = 42;
xmlSchemaParserCtxtPtr parserCtxt = NULL;
xmlSchemaPtr schema = NULL;
xmlSchemaValidCtxtPtr validCtxt = NULL;
xmlDocPtr xmlDocumentPointer = xmlParseMemory(xmlSource, xmlLength);
parserCtxt = xmlSchemaNewParserCtxt(xsdPath);
if (parserCtxt == NULL) {
fprintf(stderr, "Could not create XSD schema parsing context.\n");
goto leave;
}
schema = xmlSchemaParse(parserCtxt);
if (schema == NULL) {
fprintf(stderr, "Could not parse XSD schema.\n");
goto leave;
}
validCtxt = xmlSchemaNewValidCtxt(schema);
if (!validCtxt) {
fprintf(stderr, "Could not create XSD schema validation context.\n");
goto leave;
}
xmlSetStructuredErrorFunc(NULL, NULL);
xmlSetGenericErrorFunc(NULL, handleValidationError);
xmlThrDefSetStructuredErrorFunc(NULL, NULL);
xmlThrDefSetGenericErrorFunc(NULL, handleValidationError);
result = xmlSchemaValidateDoc(validCtxt, xmlDocumentPointer);
leave:
if (parserCtxt) {
xmlSchemaFreeParserCtxt(parserCtxt);
}
if (schema) {
xmlSchemaFree(schema);
}
if (validCtxt) {
xmlSchemaFreeValidCtxt(validCtxt);
}
printf("\n");
printf("Validation successful: %s (result: %d)\n", (result == 0) ? "YES" : "NO", result);
return 0;
}
控制台输出:
XSD File: /Users/dephiniteloop/Desktop/xml_validate/schema.xsd
XML File: /Users/dephiniteloop/Desktop/xml_validate/test.gkml
XML Source:
<?xml version="1.0" encoding="UTF-8"?>
<foo xmlns="http://example.com/XMLSchema/1.0">
</foo>
Validation Error: Element '{http://example.com/XMLSchema/1.0}foo': No matching global declaration available for the validation root.
Validation successful: NO (result: 1845)
如果重要的话:我使用的是 OSX 10.6.7,其默认为 libxml2.dylib
(/Developer/SDKs/MacOSX10.6.sdk/usr/lib/libxml2.2.7.3.dylib)
If I run this XML validation via xmllint:
xmllint --noout --schema schema.xsd test.xml
I get this success message:
.../test.xml validates
However if I run the same validation via libxml2's C API:
int result = xmlSchemaValidateDoc(...)
I get a return value of 1845
and this failure message:
Element '{http://example.com/XMLSchema/1.0}foo': No matching global declaration available for the validation root.
Which I can make absolutely no sense of. :(
schema.xsd:
<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE xs:schema PUBLIC "-//W3C//DTD XMLSCHEMA 200102//EN" "XMLSchema.dtd" >
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="http://example.com/XMLSchema/1.0" targetNamespace="http://example.com/XMLSchema/1.0" elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:element name="foo">
</xs:element>
</xs:schema>
test.xml:
<?xml version="1.0" encoding="UTF-8"?>
<foo xmlns="http://example.com/XMLSchema/1.0">
</foo>
main.c:
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <string.h>
#include <libxml/parser.h>
#include <libxml/valid.h>
#include <libxml/xmlschemas.h>
u_int32_t get_file_size(const char *file_name) {
struct stat buf;
if ( stat(file_name, &buf) != 0 ) return(0);
return (unsigned int)buf.st_size;
}
void handleValidationError(void *ctx, const char *format, ...) {
char *errMsg;
va_list args;
va_start(args, format);
vasprintf(&errMsg, format, args);
va_end(args);
fprintf(stderr, "Validation Error: %s", errMsg);
free(errMsg);
}
int main (int argc, const char * argv[]) {
const char *xsdPath = argv[1];
const char *xmlPath = argv[2];
printf("\n");
printf("XSD File: %s\n", xsdPath);
printf("XML File: %s\n", xmlPath);
int xmlLength = get_file_size(xmlPath);
char *xmlSource = (char *)malloc(sizeof(char) * xmlLength);
FILE *p = fopen(xmlPath, "r");
char c;
unsigned int i = 0;
while ((c = fgetc(p)) != EOF) {
xmlSource[i++] = c;
}
printf("\n");
printf("XML Source:\n\n%s\n", xmlSource);
fclose(p);
printf("\n");
int result = 42;
xmlSchemaParserCtxtPtr parserCtxt = NULL;
xmlSchemaPtr schema = NULL;
xmlSchemaValidCtxtPtr validCtxt = NULL;
xmlDocPtr xmlDocumentPointer = xmlParseMemory(xmlSource, xmlLength);
parserCtxt = xmlSchemaNewParserCtxt(xsdPath);
if (parserCtxt == NULL) {
fprintf(stderr, "Could not create XSD schema parsing context.\n");
goto leave;
}
schema = xmlSchemaParse(parserCtxt);
if (schema == NULL) {
fprintf(stderr, "Could not parse XSD schema.\n");
goto leave;
}
validCtxt = xmlSchemaNewValidCtxt(schema);
if (!validCtxt) {
fprintf(stderr, "Could not create XSD schema validation context.\n");
goto leave;
}
xmlSetStructuredErrorFunc(NULL, NULL);
xmlSetGenericErrorFunc(NULL, handleValidationError);
xmlThrDefSetStructuredErrorFunc(NULL, NULL);
xmlThrDefSetGenericErrorFunc(NULL, handleValidationError);
result = xmlSchemaValidateDoc(validCtxt, xmlDocumentPointer);
leave:
if (parserCtxt) {
xmlSchemaFreeParserCtxt(parserCtxt);
}
if (schema) {
xmlSchemaFree(schema);
}
if (validCtxt) {
xmlSchemaFreeValidCtxt(validCtxt);
}
printf("\n");
printf("Validation successful: %s (result: %d)\n", (result == 0) ? "YES" : "NO", result);
return 0;
}
console output:
XSD File: /Users/dephiniteloop/Desktop/xml_validate/schema.xsd
XML File: /Users/dephiniteloop/Desktop/xml_validate/test.gkml
XML Source:
<?xml version="1.0" encoding="UTF-8"?>
<foo xmlns="http://example.com/XMLSchema/1.0">
</foo>
Validation Error: Element '{http://example.com/XMLSchema/1.0}foo': No matching global declaration available for the validation root.
Validation successful: NO (result: 1845)
In case it matters: I'm on OSX 10.6.7 with its default libxml2.dylib
(/Developer/SDKs/MacOSX10.6.sdk/usr/lib/libxml2.2.7.3.dylib)
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在gnome项目的xml邮件列表上获得一些帮助后,我的错误似乎不是由我的错误引起的,而是而是由OSX 10.6.x 的 libxml2 发行版 (v2.7.3)。
(如:相同的代码适用于其他人,但对我来说 OSX 的旧版发行版失败)
我检查了 libxml2 发行说明并发现了两个候选者:
更新 2.7.4 的发行说明列出了以下错误修复:
更新 2.7.8 的发行说明列出了以下错误修复:
尚未成功不过,让 libxml2 的最新版本(v2.7.8)与我的项目(或者更确切地说是 Xcode)一起使用。
After getting some help on the gnome project's xml mailing-list it appears as if my error is not caused by a bug of mine, but rather by a bug of OSX 10.6.x's distribution (v2.7.3) of libxml2.
(as in: same code works for others, yet fails for me OSX' legacy distribution)
I checked the libxml2 release notes and found two candidates:
Release notes of Update 2.7.4 list the following bug fix:
Release notes of Update 2.7.8 list the following bug fix:
Haven't yet had success getting the latest build (v2.7.8) of libxml2 to work with my project (or rather Xcode in general) though.
我在 Ubuntu Linux 上尝试了你的内容和代码。工作没有任何异议。
构建命令:
运行命令:
输出:
XML 源:
验证成功:是(结果:0)
I tried your content and code on Ubuntu Linux. Worked without any objection.
Build command:
Run command:
Output:
XML Source:
Validation successful: YES (result: 0)
您的架构将元素 foo 放入 targetNamespace 中(这就是 elementdefault="qualified" 的含义),但您的实例文档没有声明该名称空间或任何其他名称空间。所以 foo 实际上并不匹配。
Your schema puts the element foo into the targetNamespace (that's what elementdefault="qualified" means), but your instance document doesn't declare that namespace or any other. So the foos don't actually match.