base64

I have a site I'm scraping that's doing some moderately crazy stuff -- including an external call to a page that returns a javascript chunk that decodes an embedded base64 string containing HTML that it then displays.

Was out looking for a library that would do a base64 decode for me but noticed a lot of people are using local libraries (like Sun) that have the function in them -- it's sneaky but works.

So does screen-scraper have a base64 decoder function I can mooch off? If not, does anyone have a preferred library they're using?

Terribly sorry for the long

Terribly sorry for the long delay. I don't believe we package anything into SS to do that. So, you'll probably have to whip something up from others' code... I'm not perfectly sure what you would like to do, but browsing around, I came across this, which might help somehow... It's written to be a full Java class, but could be converted to Beanshell use if you wanted to do it that way.

Either that, or compile it into a JAR file and then put into your ssDirectory/lib/ext folder. After restarting screen-scraper, you can import the package like normal, making use of the class. It was built to do conversions both ways, so take from it what you will :P

Taken from http://www.source-code.biz/snippets/java/Base64Coder.java.txt

public class Base64Coder {

// Mapping table from 6-bit nibbles to Base64 characters.
private static char[] map1 = new char[64];
static {
int i=0;
for (char c='A'; c<='Z'; c++) map1[i++] = c;
for (char c='a'; c<='z'; c++) map1[i++] = c;
for (char c='0'; c<='9'; c++) map1[i++] = c;
map1[i++] = '+'; map1[i++] = '/'; }

// Mapping table from Base64 characters to 6-bit nibbles.
private static byte[] map2 = new byte[128];
static {
for (int i=0; i for (int i=0; i<64; i++) map2[map1[i]] = (byte)i; }

/**
* Encodes a string into Base64 format.
* No blanks or line breaks are inserted.
* @param s a String to be encoded.
* @return A String with the Base64 encoded data.
*/
public static String encodeString (String s) {
return new String(encode(s.getBytes())); }

/**
* Encodes a byte array into Base64 format.
* No blanks or line breaks are inserted.
* @param in an array containing the data bytes to be encoded.
* @return A character array with the Base64 encoded data.
*/
public static char[] encode (byte[] in) {
return encode(in,in.length); }

/**
* Encodes a byte array into Base64 format.
* No blanks or line breaks are inserted.
* @param in an array containing the data bytes to be encoded.
* @param iLen number of bytes to process in in.
* @return A character array with the Base64 encoded data.
*/
public static char[] encode (byte[] in, int iLen) {
int oDataLen = (iLen*4+2)/3; // output length without padding
int oLen = ((iLen+2)/3)*4; // output length including padding
char[] out = new char[oLen];
int ip = 0;
int op = 0;
while (ip < iLen) {
int i0 = in[ip++] & 0xff;
int i1 = ip < iLen ? in[ip++] & 0xff : 0;
int i2 = ip < iLen ? in[ip++] & 0xff : 0;
int o0 = i0 >>> 2;
int o1 = ((i0 & 3) << 4) | (i1 >>> 4);
int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
int o3 = i2 & 0x3F;
out[op++] = map1[o0];
out[op++] = map1[o1];
out[op] = op < oDataLen ? map1[o2] : '='; op++;
out[op] = op < oDataLen ? map1[o3] : '='; op++; }
return out; }

/**
* Decodes a string from Base64 format.
* @param s a Base64 String to be decoded.
* @return A String containing the decoded data.
* @throws IllegalArgumentException if the input is not valid Base64 encoded data.
*/
public static String decodeString (String s) {
return new String(decode(s)); }

/**
* Decodes a byte array from Base64 format.
* @param s a Base64 String to be decoded.
* @return An array containing the decoded data bytes.
* @throws IllegalArgumentException if the input is not valid Base64 encoded data.
*/
public static byte[] decode (String s) {
return decode(s.toCharArray()); }

/**
* Decodes a byte array from Base64 format.
* No blanks or line breaks are allowed within the Base64 encoded data.
* @param in a character array containing the Base64 encoded data.
* @return An array containing the decoded data bytes.
* @throws IllegalArgumentException if the input is not valid Base64 encoded data.
*/
public static byte[] decode (char[] in) {
int iLen = in.length;
if (iLen%4 != 0) throw new IllegalArgumentException ("Length of Base64 encoded input string is not a multiple of 4.");
while (iLen > 0 && in[iLen-1] == '=') iLen--;
int oLen = (iLen*3) / 4;
byte[] out = new byte[oLen];
int ip = 0;
int op = 0;
while (ip < iLen) {
int i0 = in[ip++];
int i1 = in[ip++];
int i2 = ip < iLen ? in[ip++] : 'A';
int i3 = ip < iLen ? in[ip++] : 'A';
if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127)
throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
int b0 = map2[i0];
int b1 = map2[i1];
int b2 = map2[i2];
int b3 = map2[i3];
if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0)
throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
int o0 = ( b0 <<2) | (b1>>>4);
int o1 = ((b1 & 0xf)<<4) | (b2>>>2);
int o2 = ((b2 & 3)<<6) | b3;
out[op++] = (byte)o0;
if (op if (op return out; }

// Dummy constructor.
private Base64Coder() {}

}