NavigateXmlExample
En este ejemplo se escribe XML en un búfer XML y, a continuación, se vuelve a leer.
NavigateXml.cpp
//------------------------------------------------------------
// Copyright (C) Microsoft. All rights reserved.
//------------------------------------------------------------
#ifndef UNICODE
#define UNICODE
#endif
#include <windows.h>
#include <stdio.h>
#include "WebServices.h"
#include "process.h"
#include "string.h"
#pragma comment(lib, "WebServices.lib")
// Print out rich error info
void PrintError(HRESULT errorCode, WS_ERROR* error)
{
wprintf(L"Failure: errorCode=0x%lx\n", errorCode);
if (errorCode == E_INVALIDARG || errorCode == WS_E_INVALID_OPERATION)
{
// Correct use of the APIs should never generate these errors
wprintf(L"The error was due to an invalid use of an API. This is likely due to a bug in the program.\n");
DebugBreak();
}
HRESULT hr = NOERROR;
if (error != NULL)
{
ULONG errorCount;
hr = WsGetErrorProperty(error, WS_ERROR_PROPERTY_STRING_COUNT, &errorCount, sizeof(errorCount));
if (FAILED(hr))
{
goto Exit;
}
for (ULONG i = 0; i < errorCount; i++)
{
WS_STRING string;
hr = WsGetErrorString(error, i, &string);
if (FAILED(hr))
{
goto Exit;
}
wprintf(L"%.*s\n", string.length, string.chars);
}
}
Exit:
if (FAILED(hr))
{
wprintf(L"Could not get error string (errorCode=0x%lx)\n", hr);
}
}
static WS_XML_STRING productNameLocalName = WS_XML_STRING_VALUE("ProductName");
static WS_XML_STRING purchaseOrderLocalName = WS_XML_STRING_VALUE("PurchaseOrder");
static WS_XML_STRING purchaseOrderNamespace = WS_XML_STRING_VALUE("http://example.com");
// Main entry point
int __cdecl wmain(int argc, __in_ecount(argc) wchar_t **argv)
{
UNREFERENCED_PARAMETER(argc);
UNREFERENCED_PARAMETER(argv);
HRESULT hr = NOERROR;
WS_ERROR* error = NULL;
WS_HEAP* heap = NULL;
WS_XML_WRITER* xmlWriter = NULL;
WS_XML_BUFFER* xmlBuffer = NULL;
WS_XML_READER* xmlReader = NULL;
WS_STRING productNames[4] = {
WS_STRING_VALUE(L"Pencil"),
WS_STRING_VALUE(L"Ruler"),
WS_STRING_VALUE(L"Eraser"),
WS_STRING_VALUE(L"Pen")
};
// Create an error object for storing rich error information
hr = WsCreateError(
NULL,
0,
&error);
if (FAILED(hr))
{
goto Exit;
}
hr = WsCreateHeap(/* maxSize */ 65536, /* trimSize */ 4096, NULL, 0, &heap, error);
if (FAILED(hr))
{
goto Exit;
}
// Create an XML writer
hr = WsCreateWriter(
NULL,
0,
&xmlWriter,
error);
if (FAILED(hr))
{
goto Exit;
}
// Create an XML buffer on the specified heap
hr = WsCreateXmlBuffer(
heap,
NULL,
0,
&xmlBuffer,
error);
if (FAILED(hr))
{
goto Exit;
}
// Set the writer to output to the XML buffer
hr = WsSetOutputToBuffer(
xmlWriter,
xmlBuffer,
NULL,
0,
error);
if (FAILED(hr))
{
goto Exit;
}
// Write purchase order start element
hr = WsWriteStartElement(xmlWriter, NULL, &purchaseOrderLocalName, &purchaseOrderNamespace, error);
if (FAILED(hr))
{
goto Exit;
}
for (ULONG i = 0; i < 4; i++)
{
// Write product name start element
hr = WsWriteStartElement(xmlWriter, NULL, &productNameLocalName, &purchaseOrderNamespace, error);
if (FAILED(hr))
{
goto Exit;
}
// Write product name
hr = WsWriteChars(xmlWriter, productNames[i].chars, productNames[i].length, error);
if (FAILED(hr))
{
goto Exit;
}
// Write product name end element
hr = WsWriteEndElement(xmlWriter, error);
if (FAILED(hr))
{
goto Exit;
}
}
// Write purchase order end element
hr = WsWriteEndElement(xmlWriter, error);
if (FAILED(hr))
{
goto Exit;
}
// Flush writer so all XML content is put in the buffer
hr = WsFlushWriter(xmlWriter, 0, NULL, error);
if (FAILED(hr))
{
goto Exit;
}
// Create an XML reader
hr = WsCreateReader(
NULL,
0,
&xmlReader,
error);
if (FAILED(hr))
{
goto Exit;
}
// Set the reader input to current position of XML buffer
hr = WsSetInputToBuffer(xmlReader, xmlBuffer, NULL, 0, error);
if (FAILED(hr))
{
goto Exit;
}
// Navigate to the purchase order
hr = WsMoveReader(xmlReader, WS_MOVE_TO_ROOT_ELEMENT, NULL, error);
if (FAILED(hr))
{
goto Exit;
}
// Navigate to the first child element
hr = WsMoveReader(xmlReader, WS_MOVE_TO_CHILD_ELEMENT, NULL, error);
if (FAILED(hr))
{
goto Exit;
}
// Record the position of each product
WS_XML_NODE_POSITION productPositions[16];
ULONG productCount = 0;
for (;;)
{
BOOL found;
// Read to product name element
hr = WsReadToStartElement(xmlReader, &productNameLocalName, &purchaseOrderNamespace, &found, error);
if (FAILED(hr))
{
goto Exit;
}
if (!found)
{
break;
}
if (productCount >= WsCountOf(productPositions))
{
hr = E_FAIL;
goto Exit;
}
// Record product position
hr = WsGetReaderPosition(xmlReader, &productPositions[productCount], error);
if (FAILED(hr))
{
goto Exit;
}
productCount++;
// Skip element
hr = WsSkipNode(xmlReader, error);
if (FAILED(hr))
{
goto Exit;
}
}
// Move to each product in reverse and print out the contents
for (ULONG i = productCount; i > 0; i--)
{
hr = WsSetReaderPosition(xmlReader, &productPositions[i - 1], error);
if (FAILED(hr))
{
goto Exit;
}
hr = WsReadStartElement(xmlReader, error);
if (FAILED(hr))
{
goto Exit;
}
// Read product name into buffer
WCHAR productName[100];
ULONG length = 0;
ULONG available = WsCountOf(productName) - 1; // leave space for terminating '\0'
for (;;)
{
// Read next block of chars
ULONG charsRead;
hr = WsReadChars(xmlReader, &productName[length], available, &charsRead, error);
if (FAILED(hr))
{
goto Exit;
}
if (charsRead == 0)
{
// No more chars
break;
}
length += charsRead;
available -= charsRead;
if (available == 0)
{
hr = E_FAIL;
goto Exit;
}
}
// Zero terminate product name string
productName[length] = L'\0';
// Print out purchase order contents
wprintf(L"%s\n",
productName);
hr = WsReadEndElement(xmlReader, error);
if (FAILED(hr))
{
goto Exit;
}
}
Exit:
if (FAILED(hr))
{
// Print out the error
PrintError(hr, error);
}
fflush(
stdout);
if (heap != NULL)
{
WsFreeHeap(heap);
}
if (xmlWriter != NULL)
{
WsFreeWriter(xmlWriter);
}
if (xmlReader != NULL)
{
WsFreeReader(xmlReader);
}
if (error != NULL)
{
WsFreeError(error);
}
fflush(stdout);
return SUCCEEDED(hr) ? 0 : -1;
}