iPhone XML请求

Question

我有一个 API 可以向服务器发送 XML 请求:

<?xml version="1.0" encoding="UTF-8"?>
<request type="handle" action="update">
<userdata>
<username>YourUsername</username>
<password>YourPassword</password>
</userdata>
<handledata type="PERSON" id="HandleId">
<name>Mustermann</name>
<firstname>Max</firstname>
<organization>Firma KG</organization>
<street>Musterstrasse 1</street>
<postalcode>11111</postalcode>
<city>Musterstadt</city>
<state>Niedersachsen</state>
<country>DE</country>
<email>email@adresse.de</email>
<phone>+43-111-111111</phone>
<fax>+43-111-111111</fax>
<remarks>remarks</remarks>
</handledata>
</request>

如何在 iPhone 上执行此操作？

Answer 1

您可以使用libxml2。我怀疑这是最快的方法。将其框架添加到您的项目中(请参阅 this document 的“设置您的项目”部分)。

在您的 XML 编写器的 header 中，添加以下导入:

#import <libxml/encoding.h>
#import <libxml/xmlwriter.h>

在实现中，编写一个方法来生成您的 XML。假设您将通过 NSData* 对象发送请求的字节，因此您可能会这样写:

- (NSData *) xmlDataFromRequest 
{
    xmlTextWriterPtr _writer;
    xmlBufferPtr _buf;
    xmlChar *_tmp;
    const char *_UTF8Encoding = "UTF-8";

    _buf = xmlBufferCreate();
    _writer = xmlNewTextWriterMemory(_buf, 0);

    // <?xml version="1.0" encoding="UTF-8"?>
    xmlTextWriterStartDocument(_writer, "1.0", _UTF8Encoding, NULL);

    // <request type="handle" action="update">
    xmlTextWriterStartElement(_writer, BAD_CAST "request");
    xmlTextWriterWriteAttribute(_writer, BAD_CAST "type", BAD_CAST "handle");
    xmlTextWriterWriteAttribute(_writer, BAD_CAST "action", BAD_CAST "update");
    xmlTextWriterEndElement(_writer);

    // <userdata>...</userdata>
    xmlTextWriterStartElement(_writer, BAD_CAST "userdata");
    xmlTextWriterStartElement(_writer, BAD_CAST "username");
    _tmp = [self xmlCharPtrForInput:[[NSString stringWithFormat:@"YourUsername"] cStringUsingEncoding:NSUTF8StringEncoding] withEncoding:_UTF8Encoding];
    xmlTextWriterWriteString(_writer, _tmp);
    xmlTextWriterEndElement(_writer); // closing <username>
    xmlFree(_tmp);
    xmlTextWriterStartElement(_writer, BAD_CAST "password");
    _tmp = [self xmlCharPtrForInput:[[NSString stringWithFormat:@"YourPassword"] cStringUsingEncoding:NSUTF8StringEncoding] withEncoding:_UTF8Encoding];
    xmlTextWriterWriteString(_writer, _tmp);
    xmlTextWriterEndElement(_writer); // closing <password>
    xmlFree(_tmp); 
    xmlTextWriterEndElement(_writer); // closing <userdata>

    // etc.

    xmlTextWriterEndDocument(_writer);
    xmlFreeTextWriter(_writer);

    // turn libxml2 buffer into NSData* object

    NSData *_xmlData = [NSData dataWithBytes:(_buf->content) length:(_buf->use)];
    xmlBufferFree(_buf);

    return _xmlData;
}

我这里有一个辅助方法，用于将 const char * 转换为 xmlChar *:

- (xmlChar *) xmlCharPtrForInput:(const char *)_input withEncoding:(const char *)_encoding 
{
    xmlChar *_output;
    int _ret;
    int _size;
    int _outputSize;
    int _temp;
    xmlCharEncodingHandlerPtr _handler;

    if (_input == 0)
        return 0;

    _handler = xmlFindCharEncodingHandler(_encoding);

    if (!_handler) {
        NSLog(@"convertInput: no encoding handler found for '%s'\n", (_encoding ? _encoding : ""));
        return 0;
    }

    _size = (int) strlen(_input) + 1;
    _outputSize = _size * 2 - 1;
    _output = (unsigned char *) xmlMalloc((size_t) _outputSize);

    if (_output != 0) {
        _temp = _size - 1;
        _ret = _handler->input(_output, &_outputSize, (const xmlChar *) _input, &_temp);
        if ((_ret < 0) || (_temp - _size + 1)) {
            if (_ret < 0) {
                NSLog(@"convertInput: conversion wasn't successful.\n");
            } else {
                NSLog(@"convertInput: conversion wasn't successful. Converted: %i octets.\n", _temp);
            }   
            xmlFree(_output);
            _output = 0;
        } else {
            _output = (unsigned char *) xmlRealloc(_output, _outputSize + 1);
            _output[_outputSize] = 0;  /*null terminating out */
        }
    } else {
        NSLog(@"convertInput: no memory\n");
    }

    return _output;
}