使用libxml2进行xml开发（一）

（一）Windows下使用MinGW和Code::Blocks环境配置libxml2

笔者此次是在windows 7下使用MinGW和Code::Blocks开发C程式的，手上的一个项目需要使用socket通讯接收远端主机发来的xml报文，使用C程式解析，所以需要配置libxml2。

首先先到http://xmlsoft.org/sources/win32/下载好libxml2、iconv和zlib的包，并将其对应的bin、include、lib中的内容复制到MinGW对应的bin、include、lib目录中去（libxml2是基于iconv和zlib的

在CB中建立好一个工程后，在settings->compiler->linker settings中添加上述包中的lib（已经添加到MinGW\lib下了），我们可以用libxml2官方的一个例子来测试我们的配置：

将gjobs.xml放在工程文件夹中，将其设置为输入  Project->set programs' arguments

http://www.ualberta.ca/dept/aict/uts/software/solaris9/sparc/patches/solaris/9_Recommended/114014-18/SUNWlxmlS/reloc/usr/share/src/libxml2/example/gjobread.c

http://www.ualberta.ca/dept/aict/uts/software/solaris9/sparc/patches/solaris/9_Recommended/114014-18/SUNWlxmlS/reloc/usr/share/src/libxml2/example/gjobs.xml

笔者在编译成功后，运行的时候遇到过如下的一个错误

“无法定位程序输入点gzdirect于动态链接库zlib1.dll”

解决办法是使用http://www.zlib.net/下载的最新的zlib1.dll替换WINDOWS/system32文件夹下的zlib1.dll （window下优先使用system32下的这个dll，而在安装某些软件时会将它们的zlib1.dll放到system32中，造成版本过低）

运行结果：

附gjobread.c和gjobs.xml源码

 /*
  * gjobread.c : a small test program for gnome jobs XML format
  *
  * See Copyright for the status of this software.
  *
  * Daniel.Veillard@w3.org
  */

 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>

 /*
  * This example should compile and run indifferently with libxml-1.8.8 +
  * and libxml2-2.1.0 +
  * Check the COMPAT comments below
  */

 /*
  * COMPAT using xml-config --cflags to get the include path this will
  * work with both
  */
 #include <libxml/xmlmemory.h>
 #include <libxml/parser.h>

 #define DEBUG(x) printf(x)

 /*
  * A person record
  * an xmlChar * is really an UTF8 encoded char string (0 terminated)
  */
 typedef struct person {
     xmlChar *name;
     xmlChar *email;
     xmlChar *company;
     xmlChar *organisation;
     xmlChar *smail;
     xmlChar *webPage;
     xmlChar *phone;
 } person, *personPtr;

 /*
  * And the code needed to parse it
  */
 static personPtr
 parsePerson(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
     personPtr ret = NULL;

 DEBUG("parsePerson\n");
     /*
      * allocate the struct
      */
     ret = (personPtr) malloc(sizeof(person));
     if (ret == NULL) {
         fprintf(stderr,"out of memory\n");
     return(NULL);
     }
     memset(ret, , sizeof(person));

     /* We don't care what the top level element name is */
     /* COMPAT xmlChildrenNode is a macro unifying libxml1 and libxml2 names */
     cur = cur->xmlChildrenNode;
     while (cur != NULL) {
         if ((!xmlStrcmp(cur->name, (const xmlChar *)"Person")) &&
         (cur->ns == ns))
         ret->name = xmlNodeListGetString(doc, cur->xmlChildrenNode, );
         if ((!xmlStrcmp(cur->name, (const xmlChar *)"Email")) &&
         (cur->ns == ns))
         ret->email = xmlNodeListGetString(doc, cur->xmlChildrenNode, );
     cur = cur->next;
     }

     return(ret);
 }

 /*
  * and to print it
  */
 static void
 printPerson(personPtr cur) {
     if (cur == NULL) return;
     printf("------ Person\n");
     if (cur->name) printf("    name: %s\n", cur->name);
     if (cur->email) printf("    email: %s\n", cur->email);
     if (cur->company) printf("    company: %s\n", cur->company);
     if (cur->organisation) printf("    organisation: %s\n", cur->organisation);
     if (cur->smail) printf("    smail: %s\n", cur->smail);
     if (cur->webPage) printf("    Web: %s\n", cur->webPage);
     if (cur->phone) printf("    phone: %s\n", cur->phone);
     printf("------\n");
 }

 /*
  * a Description for a Job
  */
 typedef struct job {
     xmlChar *projectID;
     xmlChar *application;
     xmlChar *category;
     personPtr contact;
     int nbDevelopers;
     personPtr developers[]; /* using dynamic alloc is left as an exercise */
 } job, *jobPtr;

 /*
  * And the code needed to parse it
  */
 static jobPtr
 parseJob(xmlDocPtr doc, xmlNsPtr ns, xmlNodePtr cur) {
     jobPtr ret = NULL;

 DEBUG("parseJob\n");
     /*
      * allocate the struct
      */
     ret = (jobPtr) malloc(sizeof(job));
     if (ret == NULL) {
         fprintf(stderr,"out of memory\n");
     return(NULL);
     }
     memset(ret, , sizeof(job));

     /* We don't care what the top level element name is */
     cur = cur->xmlChildrenNode;
     while (cur != NULL) {

         if ((!xmlStrcmp(cur->name, (const xmlChar *) "Project")) &&
         (cur->ns == ns)) {
         ret->projectID = xmlGetProp(cur, (const xmlChar *) "ID");
         if (ret->projectID == NULL) {
         fprintf(stderr, "Project has no ID\n");
         }
     }
         if ((!xmlStrcmp(cur->name, (const xmlChar *) "Application")) &&
             (cur->ns == ns))
         ret->application =
         xmlNodeListGetString(doc, cur->xmlChildrenNode, );
         if ((!xmlStrcmp(cur->name, (const xmlChar *) "Category")) &&
         (cur->ns == ns))
         ret->category =
         xmlNodeListGetString(doc, cur->xmlChildrenNode, );
         if ((!xmlStrcmp(cur->name, (const xmlChar *) "Contact")) &&
         (cur->ns == ns))
         ret->contact = parsePerson(doc, ns, cur);
     cur = cur->next;
     }

     return(ret);
 }

 /*
  * and to print it
  */
 static void
 printJob(jobPtr cur) {
     int i;

     if (cur == NULL) return;
     printf("=======  Job\n");
     if (cur->projectID != NULL) printf("projectID: %s\n", cur->projectID);
     if (cur->application != NULL) printf("application: %s\n", cur->application);
     if (cur->category != NULL) printf("category: %s\n", cur->category);
     if (cur->contact != NULL) printPerson(cur->contact);
     printf("%d developers\n", cur->nbDevelopers);

     for (i = ;i < cur->nbDevelopers;i++) printPerson(cur->developers[i]);
     printf("======= \n");
 }

 /*
  * A pool of Gnome Jobs
  */
 typedef struct gjob {
     int nbJobs;
     jobPtr jobs[]; /* using dynamic alloc is left as an exercise */
 } gJob, *gJobPtr;

 static gJobPtr
 parseGjobFile(char *filename) {
     xmlDocPtr doc;
     gJobPtr ret;
     jobPtr curjob;
     xmlNsPtr ns;
     xmlNodePtr cur;

     /*
      * build an XML tree from a the file;
      */
     doc = xmlParseFile(filename);
     if (doc == NULL) return(NULL);

     /*
      * Check the document is of the right kind
      */

     cur = xmlDocGetRootElement(doc);
     if (cur == NULL) {
         fprintf(stderr,"empty document\n");
     xmlFreeDoc(doc);
     return(NULL);
     }
     ns = xmlSearchNsByHref(doc, cur,
         (const xmlChar *) "http://www.gnome.org/some-location");
     if (ns == NULL) {
         fprintf(stderr,
             "document of the wrong type, GJob Namespace not found\n");
     xmlFreeDoc(doc);
     return(NULL);
     }
     if (xmlStrcmp(cur->name, (const xmlChar *) "Helping")) {
         fprintf(stderr,"document of the wrong type, root node != Helping");
     xmlFreeDoc(doc);
     return(NULL);
     }

     /*
      * Allocate the structure to be returned.
      */
     ret = (gJobPtr) malloc(sizeof(gJob));
     if (ret == NULL) {
         fprintf(stderr,"out of memory\n");
     xmlFreeDoc(doc);
     return(NULL);
     }
     memset(ret, , sizeof(gJob));

     /*
      * Now, walk the tree.
      */
     /* First level we expect just Jobs */
     cur = cur->xmlChildrenNode;
     while ( cur && xmlIsBlankNode ( cur ) )
       {
     cur = cur -> next;
       }
     if ( cur ==  )
       return ( NULL );
     if ((xmlStrcmp(cur->name, (const xmlChar *) "Jobs")) || (cur->ns != ns)) {
         fprintf(stderr,"document of the wrong type, was '%s', Jobs expected",
         cur->name);
     fprintf(stderr,"xmlDocDump follows\n");
     xmlDocDump ( stderr, doc );
     fprintf(stderr,"xmlDocDump finished\n");
     xmlFreeDoc(doc);
     free(ret);
     return(NULL);
     }

     /* Second level is a list of Job, but be laxist */
     cur = cur->xmlChildrenNode;
     while (cur != NULL) {
         if ((!xmlStrcmp(cur->name, (const xmlChar *) "Job")) &&
         (cur->ns == ns)) {
         curjob = parseJob(doc, ns, cur);
         if (curjob != NULL)
             ret->jobs[ret->nbJobs++] = curjob;
             if (ret->nbJobs >= ) break;
     }
     cur = cur->next;
     }

     return(ret);
 }

 static void
 handleGjob(gJobPtr cur) {
     int i;

     /*
      * Do whatever you want and free the structure.
      */
     printf("%d Jobs registered\n", cur->nbJobs);
     for (i = ; i < cur->nbJobs; i++) printJob(cur->jobs[i]);
 }

 int main(int argc, char **argv) {
     int i;
     gJobPtr cur;

     /* COMPAT: Do not genrate nodes for formatting spaces */
     LIBXML_TEST_VERSION
     xmlKeepBlanksDefault();

     for (i = ; i < argc ; i++) {
     cur = parseGjobFile(argv[i]);
     if ( cur )
       handleGjob(cur);
     else
       fprintf( stderr, "Error parsing file '%s'\n", argv[i]);

     }

     /* Clean up everything else before quitting. */
     xmlCleanupParser();

     return();
 }

gjobread.c

 <?xml version="1.0"?>
 <gjob:Helping xmlns:gjob="http://www.gnome.org/some-location">
   <gjob:Jobs>

     <gjob:Job>
       <gjob:Project ID="3"/>
       <gjob:Application>GBackup</gjob:Application>
       <gjob:Category>Development</gjob:Category>

       <gjob:Update>
     <gjob:Status>Open</gjob:Status>
     <gjob:Modified>Mon, 07 Jun 1999 20:27:45 -0400 MET DST</gjob:Modified>
         <gjob:Salary>USD 0.00</gjob:Salary>
       </gjob:Update>

       <gjob:Developers>
         <gjob:Developer>
         </gjob:Developer>
       </gjob:Developers>

       <gjob:Contact>
         <gjob:Person>Nathan Clemons</gjob:Person>
     <gjob:Email>nathan@windsofstorm.net</gjob:Email>
         <gjob:Company>
     </gjob:Company>
         <gjob:Organisation>
     </gjob:Organisation>
         <gjob:Webpage>
     </gjob:Webpage>
     <gjob:Snailmail>
     </gjob:Snailmail>
     <gjob:Phone>
     </gjob:Phone>
       </gjob:Contact>

       <gjob:Requirements>
       The program should be released as free software, under the GPL.
       </gjob:Requirements>

       <gjob:Skills>
       </gjob:Skills>

       <gjob:Details>
       A GNOME based system that will allow a superuser to configure
       compressed and uncompressed files and/or file systems to be backed
       up with a supported media in the system.  This should be able to
       perform via find commands generating a list of files that are passed
       to tar, dd, cpio, cp, gzip, etc., to be directed to the tape machine
       or via operations performed on the filesystem itself. Email
       notification and GUI status display very important.
       </gjob:Details>

     </gjob:Job>

   </gjob:Jobs>
 </gjob:Helping>

gjobs.xml