cn.ipokerface.weixin.request.http.HeaderValueFormatter Maven / Gradle / Ivy
package cn.ipokerface.weixin.request.http;
import cn.ipokerface.weixin.io.CharArrayBuffer;
/**
* Created by PokerFace
* Create Date 2019-12-27.
* Email: [email protected]
* Version 1.0.0
*
* Description:
*/
public class HeaderValueFormatter {
public final static HeaderValueFormatter INSTANCE = new HeaderValueFormatter();
/**
* Special characters that can be used as separators in HTTP parameters.
* These special characters MUST be in a quoted string to be used within
* a parameter value .
*/
public final static String SEPARATORS = " ;,:@()<>\\\"/[]?={}\t";
/**
* Unsafe special characters that must be escaped using the backslash
* character
*/
public final static String UNSAFE_CHARS = "\"\\";
public HeaderValueFormatter() {
super();
}
/**
* Formats a set of parameters.
*
* @param nvps the parameters to format
* @param quote true to always format with quoted values,
* false to use quotes only when necessary
* @param formatter the formatter to use, or null
* for the {@link #INSTANCE default}
*
* @return the formatted parameters
*/
public static
String formatParameters(final NameValue[] nvps,
final boolean quote,
final HeaderValueFormatter formatter) {
return (formatter != null ? formatter : HeaderValueFormatter.INSTANCE)
.formatParameters(null, nvps, quote).toString();
}
// non-javadoc, see interface HeaderValueFormatter
public CharArrayBuffer formatParameters(final CharArrayBuffer charBuffer,
final NameValue[] nvps,
final boolean quote) {
final int len = estimateParametersLen(nvps);
CharArrayBuffer buffer = charBuffer;
if (buffer == null) {
buffer = new CharArrayBuffer(len);
} else {
buffer.ensureCapacity(len);
}
for (int i = 0; i < nvps.length; i++) {
if (i > 0) {
buffer.append("; ");
}
formatNameValuePair(buffer, nvps[i], quote);
}
return buffer;
}
/**
* Estimates the length of formatted parameters.
*
* @param nvps the parameters to format, or null
*
* @return a length estimate, in number of characters
*/
protected int estimateParametersLen(final NameValue[] nvps) {
if ((nvps == null) || (nvps.length < 1)) {
return 0;
}
int result = (nvps.length-1) * 2; // "; " between the parameters
for (final NameValue nvp : nvps) {
result += estimateNameValuePairLen(nvp);
}
return result;
}
/**
* Formats a name-value pair.
*
* @param nvp the name-value pair to format
* @param quote true to always format with a quoted value,
* false to use quotes only when necessary
* @param formatter the formatter to use, or null
* for the {@link #INSTANCE default}
*
* @return the formatted name-value pair
*/
public static
String formatNameValuePair(final NameValue nvp,
final boolean quote,
final HeaderValueFormatter formatter) {
return (formatter != null ? formatter : HeaderValueFormatter.INSTANCE)
.formatNameValuePair(null, nvp, quote).toString();
}
// non-javadoc, see interface HeaderValueFormatter
public CharArrayBuffer formatNameValuePair(final CharArrayBuffer charBuffer,
final NameValue nvp,
final boolean quote) {
final int len = estimateNameValuePairLen(nvp);
CharArrayBuffer buffer = charBuffer;
if (buffer == null) {
buffer = new CharArrayBuffer(len);
} else {
buffer.ensureCapacity(len);
}
buffer.append(nvp.getName());
final String value = nvp.getValue();
if (value != null) {
buffer.append('=');
doFormatValue(buffer, value, quote);
}
return buffer;
}
/**
* Estimates the length of a formatted name-value pair.
*
* @param nvp the name-value pair to format, or null
*
* @return a length estimate, in number of characters
*/
protected int estimateNameValuePairLen(final NameValue nvp) {
if (nvp == null) {
return 0;
}
int result = nvp.getName().length(); // name
final String value = nvp.getValue();
if (value != null) {
// assume quotes, but no escaped characters
result += 3 + value.length(); // ="value"
}
return result;
}
/**
* Actually formats the value of a name-value pair.
* This does not include a leading = character.
* Called from {@link #formatNameValuePair formatNameValuePair}.
*
* @param buffer the buffer to append to, never null
* @param value the value to append, never null
* @param quote true to always format with quotes,
* false to use quotes only when necessary
*/
protected void doFormatValue(final CharArrayBuffer buffer,
final String value,
final boolean quote) {
boolean quoteFlag = quote;
if (!quoteFlag) {
for (int i = 0; (i < value.length()) && !quoteFlag; i++) {
quoteFlag = isSeparator(value.charAt(i));
}
}
if (quoteFlag) {
buffer.append('"');
}
for (int i = 0; i < value.length(); i++) {
final char ch = value.charAt(i);
if (isUnsafe(ch)) {
buffer.append('\\');
}
buffer.append(ch);
}
if (quoteFlag) {
buffer.append('"');
}
}
/**
* Checks whether a character is a {@link #SEPARATORS separator}.
*
* @param ch the character to check
*
* @return true if the character is a separator,
* false otherwise
*/
protected boolean isSeparator(final char ch) {
return SEPARATORS.indexOf(ch) >= 0;
}
/**
* Checks whether a character is {@link #UNSAFE_CHARS unsafe}.
*
* @param ch the character to check
*
* @return true if the character is unsafe,
* false otherwise
*/
protected boolean isUnsafe(final char ch) {
return UNSAFE_CHARS.indexOf(ch) >= 0;
}
}