/**
* @param cssFilePath - path of the cssFile
* @param contextPath - web app context path or custom context path
* @param inputStream - input stream
* @param outputStream - output stream
* @throws java.io.IOException - throws exception in case something woes wrong (IO read/write)
*/
private void processCSS(
String contextPath, String cssFilePath, InputStream inputStream, OutputStream outputStream)
throws IOException {
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
String line;
StringBuffer buffer = new StringBuffer();
while ((line = bufferedReader.readLine()) != null) {
buffer.setLength(0);
buffer.append(line);
line = this.processCSSLine(context, contextPath, cssFilePath, buffer);
outputStream.write((line + "\n").getBytes());
}
}
/**
* @param context - ServletContext
* @param contextPath - context path or custom configured context path
* @param cssFilePath - css file path
* @param line - one single line in a css file
* @return processed string with appropriate replacement of image URLs if any
*/
private String processCSSLine(
ServletContext context, String contextPath, String cssFilePath, StringBuffer line) {
Matcher matcher = CSS_IMG_URL_PATTERN.matcher(line);
String cssRealPath = context.getRealPath(cssFilePath);
while (matcher.find()) {
String refImgPath = matcher.group(1);
if (!Utils.isProtocolURL(refImgPath)) { // ignore absolute protocol paths
String resolvedImgPath = refImgPath;
if (!refImgPath.startsWith("/")) {
resolvedImgPath = Utils.buildProperPath(Utils.getParentPath(cssFilePath), refImgPath);
}
String imgRealPath = context.getRealPath(resolvedImgPath);
String fingerPrint = Utils.buildETagForResource(resolvedImgPath, context);
int offset = line.indexOf(refImgPath);
line.replace(
offset, // from
offset + refImgPath.length(), // to
contextPath + Utils.addFingerPrint(fingerPrint, resolvedImgPath));
Utils.updateReferenceMap(cssRealPath, imgRealPath);
}
}
return line.toString();
}