/**
* @return The HTTP-authentication object or null if there is no supported scheme in the header.
* If there are several valid schemes present, we pick the strongest one. If there are several
* schemes of the same strength, we pick the one that comes first.
*/
private HttpAuthHeader parseAuthHeader(String header) {
if (header != null) {
int posMax = 256;
int posLen = 0;
int[] pos = new int[posMax];
int headerLen = header.length();
if (headerLen > 0) {
// first, we find all unquoted instances of 'Basic' and 'Digest'
boolean quoted = false;
for (int i = 0; i < headerLen && posLen < posMax; ++i) {
if (header.charAt(i) == '\"') {
quoted = !quoted;
} else {
if (!quoted) {
if (header.startsWith(HttpAuthHeader.BASIC_TOKEN, i)) {
pos[posLen++] = i;
continue;
}
if (header.startsWith(HttpAuthHeader.DIGEST_TOKEN, i)) {
pos[posLen++] = i;
continue;
}
}
}
}
}
if (posLen > 0) {
// consider all digest schemes first (if any)
for (int i = 0; i < posLen; i++) {
if (header.startsWith(HttpAuthHeader.DIGEST_TOKEN, pos[i])) {
String sub = header.substring(pos[i], (i + 1 < posLen ? pos[i + 1] : headerLen));
HttpAuthHeader rval = new HttpAuthHeader(sub);
if (rval.isSupportedScheme()) {
// take the first match
return rval;
}
}
}
// ...then consider all basic schemes (if any)
for (int i = 0; i < posLen; i++) {
if (header.startsWith(HttpAuthHeader.BASIC_TOKEN, pos[i])) {
String sub = header.substring(pos[i], (i + 1 < posLen ? pos[i + 1] : headerLen));
HttpAuthHeader rval = new HttpAuthHeader(sub);
if (rval.isSupportedScheme()) {
// take the first match
return rval;
}
}
}
}
}
return null;
}
