我一直在玩 gSOAP XML 数据绑定(bind),方法是将 XML 文档加载到 C++ 类中,修改数据并将其序列化回 XML。
这是 XML 的片段 - library.xml:
<?xml version="1.0" encoding="UTF-8"?>
<gt:Library xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:gt="http://www.bk.com/gSOAP/test">
<gt:Books>
<gt:Book isbn="0132350882" author="Robert C. Martin" title="Clean Code">
<gt:CopiesAvailable>2</gt:CopiesAvailable>
</gt:Book>
<gt:Book isbn="020161622X" author="Andrew Hunt" title="The Pragmatic Programmer">
<gt:CopiesAvailable>0</gt:CopiesAvailable>
</gt:Book>
<gt:Book isbn="0201633612" author="Erich Gamma" title="Design patterns">
<gt:CopiesAvailable>1</gt:CopiesAvailable>
</gt:Book>
</gt:Books>
...
</gt:Library>
以下代码将 XML 加载到对象中,修改对象并将其序列化回 XML。 请注意,XML 是通过文件流从文件中加载的,要添加的数据是通过标准输入 (cin) 从用户处获取的。
主要.cpp:
#include "soapH.h"
#include "gt.nsmap"
#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
using std::cin;
using std::cout;
using std::endl;
using std::ifstream;
using std::ofstream;
using std::fstream;
using std::string;
using std::stringstream;
void DisplayAllBooks(const _gt__Library& library)
{
cout << "\n\nDisplaying all books in the library:" << endl;
std::vector<_gt__Library_Books_Book>::const_iterator it = library.Books.Book.begin();
for(;it != library.Books.Book.end(); it++)
{
cout << "\nBook:\n" << "\tTitle:" << (*it).title << "\n\tAuthor:" << (*it).author <<"\n\tISBN: " << (*it).isbn << "\n\tCopies available: " << static_cast<int>((*it).CopiesAvailable) << endl;
}
}
void AddBook(_gt__Library& library)
{
cout << "\n\nAdding a new book:" << endl;
_gt__Library_Books_Book book;
cout << "\tTitle: " << std::flush;
getline(cin, book.title);
cout << "\tAuthor: " << std::flush;
getline(cin, book.author);
cout << "\tISBN:" << std::flush;
getline(cin, book.isbn);
cout << "\tCopies available: " << std::flush;
string strCopiesAvailable;
getline(cin, strCopiesAvailable);
stringstream ss(strCopiesAvailable);
ss >> book.CopiesAvailable;
library.Books.Book.push_back(book);
}
// Terminate and destroy soap
void DestroySoap(struct soap* pSoap)
{
// remove deserialized class instances (C++ objects)
soap_destroy(pSoap);
// clean up and remove deserialized data
soap_end(pSoap);
// detach context (last use and no longer in scope)
soap_done(pSoap);
}
int main()
{
//
// Create and intialize soap
//
// gSOAP runtime context
struct soap soap;
// initialize runtime context
soap_init(&soap);
// Set input mode
soap_imode(&soap, SOAP_ENC_XML);
// reset deserializers; start new (de)serialization phase
soap_begin(&soap);
//
// Load XML (Deserialize)
//
_gt__Library library;
string strXML = "library.xml";
ifstream fstreamIN(strXML);
soap.is = &fstreamIN;
// calls soap_begin_recv, soap_get__gt__Library and soap_end_recv
if(soap_read__gt__Library(&soap, &library) != SOAP_OK)
{
std::cout << "soap_read__gt__Library() failed" << std::endl;
DestroySoap(&soap);
return 1;
}
fstreamIN.close();
//
// Display books before and after adding a new book
//
DisplayAllBooks(library);
AddBook(library);
DisplayAllBooks(library);
//
// Serialize
//
soap_set_omode(&soap, SOAP_XML_INDENT);
ofstream fstreamOUT("library.xml");
soap.os = &fstreamOUT;
// calls soap_begin_send, soap_serialize, soap_put and soap_end_send
if(soap_write__gt__Library(&soap, &library) != SOAP_OK)
{
std::cout << "soap_write__gt__Library() failed" << std::endl;
DestroySoap(&soap);
return 1;
}
fstreamOUT.close();
DestroySoap(&soap);
return 0;
}
运行此测试应用程序后,一切正常,除了所有新添加的元素都有以回车符结尾的字符串(CR -
):
修改后的 XML 如下所示:
<?xml version="1.0" encoding="UTF-8"?>
<gt:Library xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:gt="http://www.bk.com/gSOAP/test">
<gt:Books>
<gt:Book isbn="0132350882" author="Robert C. Martin" title="Clean Code">
<gt:CopiesAvailable>2</gt:CopiesAvailable>
</gt:Book>
<gt:Book isbn="020161622X" author="Andrew Hunt" title="The Pragmatic Programmer">
<gt:CopiesAvailable>0</gt:CopiesAvailable>
</gt:Book>
<gt:Book isbn="0201633612" author="Erich Gamma" title="Design patterns">
<gt:CopiesAvailable>1</gt:CopiesAvailable>
</gt:Book>
<gt:Book isbn="12345678
" author="Scott Meyers
" title="Effective C++
">
<gt:CopiesAvailable>123</gt:CopiesAvailable>
</gt:Book>
</gt:Books>
...
</gt:Library>
我追查了错误的来源,发现了以下内容:
soap_read__gt__Library()
调用 soap_begin_send()
执行以下行:
_setmode(soap->recvfd, _O_BINARY);
soap->recvfd
在 soap_init()
中设置为 0
并且 0
是文件的值stdin
的描述符。
一旦 stdin
的模式更改为二进制,STL 库不会将 \r\n
解析为单个 \n
读取操作和 getline(cin, str)
像往常一样读取所有内容直到 \n
,将 \r
复制到输出字符串中。这正是出现在最终 XML 中的新字符串中的回车符。
我的问题是:如果数据源是文件流,为什么 gSOAP 会修改 stdin
模式?这是 gSOAP 中的错误吗?
注意:
正如预期的那样,如果 stdio
的模式在 soap_begin_send()
之后但在从 std 读取数据之前恢复为
、_O_TEXT
::cingetline()
工作正常。这是补丁:
_setmode(_fileno(stdin), _O_TEXT)
最佳答案
这是为了避免在读写 Unicode 和 UTF-8 编码的 XML 时出现编码问题。
关于c++ - 如果从文件流读取数据,为什么 gSOAP 将标准输入模式设置为二进制?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/9195635/