June 29th, 2009stuartwhitefordJavaScript, SharePoint

    I’ve been working with a serial device that captures a signature recently and one of the methods of its associated ActiveX control lets me have a VBScript array of bytes that represents the captured image. It’s a reasonably simple method to convert this into a JavaScript array of bytes and I thought that once I had this it would be easy enough to call the SharePoint web services using jQuery’s built-in AJAX methods. Calling the web service is a piece of cake but it won’t just accept an array of byes, it needs to be a Base64 encoded string, so what follows is how to get yourself one of those from the aforementioned array of bytes and pass it to the Copy web service.

    For a good description on how to achieve Base64 encoding have a look at the example on this Wikipedia page.

    Firstly, the table variable contains the allowable character in a Base64 encoded string. The OctetPad() function pads a given string parameter to 8 characters in length with zeroes. The Decimal() function accepts a string parameter in binary format and converts it to its decimal equivalent.

    The Base64String() method accepts an array of bytes and deals with them in chunks of 3 at a time. It converts each byte to a bit pattern and then concatenates them into a single bit pattern having a length of 24. This bit pattern is split into 4 chunks of 6, converted to a decimal number and the character from the table variable at the index equal to the decimal number is appended to the encoded string.

    If the length of the array is not a multiple of 3 then we deal with the remaining 1 or 2 bytes in a slightly different manner. If there are 2 bytes remaining construct the bit pattern with these 2 bytes (giving us 16 bits) and add 2 zeroes to the end to give us 18 bits (divisible by 6). In this case we manually set the fourth Base64 encoded chracter to “=”. If there is 1 byte remaining construct the bit pattern with this single byte (giving us 8 bits) and add 4 zeroes to the end to give us 12 bits (again, divisible by 6). In this case we manually set the third and fourth Base64 encoded chracters to “=”.

    var table = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    function OctetPad(str) {
        return Array(8 + 1 - str.length).join("0") + str;
    function Decimal(bin) {
        var len = bin.length;
        var ans = 0;
        var plc = len - 1;
        for (i = 0; i < len; i++) {
            if (bin.substr(i, 1) == 1) {
                ans = ans + Math.pow(2, plc);
            else if (bin.substr(i, 1) != 0) {
        return ans;
    function Base64String(bytes) {
        var base64 = "";
        while (bytes.length > 0) {
            var byte1 = null;
            var byte2 = null;
            var byte3 = null;
            var enc1 = null;
            var enc2 = null;
            var enc3 = null;
            var enc4 = null;
            byte1 = bytes.shift().toString(2);
            if (bytes.length > 0) {
                byte2 = bytes.shift().toString(2);
                if (bytes.length > 0) {
                    byte3 = bytes.shift().toString(2);
                else {
                    enc4 = "=";
            else {
                enc3 = "=";
                enc4 = "=";
            var bitPattern = OctetPad(byte1) + (byte2 != null ? OctetPad(byte2) : "00") + (byte3 != null ? OctetPad(byte3) : "00");
            enc1 = table.charAt(Decimal(bitPattern.substr(0, 6)));
            enc2 = table.charAt(Decimal(bitPattern.substr(6, 6)));
            if (enc3 == null) { enc3 = table.charAt(Decimal(bitPattern.substr(12, 6))); }
            if (enc4 == null) { enc4 = table.charAt(Decimal(bitPattern.substr(18, 6))); }
            base64 = base64 + enc1 + enc2 + enc3 + enc4;
        return base64;

    Our Upload() function makes use of the jQuery ajax method and looks like the following: -

    function Upload(jsArray, sourceUrl, destinationUrl) {
        var jsStream = Base64String(jsArray);
        var soap12Env =
            "<soap12:Envelope xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xmlns:xsd='http://www.w3.org/2001/XMLSchema' xmlns:soap12='http://www.w3.org/2003/05/soap-envelope'> 
                    <CopyIntoItems xmlns='http://schemas.microsoft.com/sharepoint/soap/'> 
                        <SourceUrl>" + sourceUrl + "</SourceUrl> 
                            <string>" + destinationUrl + "</string> 
                            <FieldInformation Type='File' /> 
                        <Stream>" + jsStream + "</Stream> 
            url: "http://sharepoint/_vti_bin/copy.asmx",
            type: "POST",
            dataType: "xml",
            data: soap12Env,
            contentType: "text/xml; charset="utf-8""

    I’ve fixed the value of the SharePoint web service URL in this function but it’s probably a better idea to have it passed in as a parameter to the function. All we’re doing here is creating a SOAP envelope for the Base64 stream of characters and the method would be called as follows: -

    var jsArray = new Array(71,73,70,56,57,97,2,0,2,0,241,0,0,255,255,0,255,0,0,51,204,0,0,0,255,44,0,0,0,0,2,0,2,0,0,2,3,12,52,5,0,59);
    var sourceUrl = "test.gif";
    var destinationUrl = "http://sharepoint/ImageLibrary/test.gif";
    Upload(jsArray, sourceUrl, destinationUrl);

    In this example I’ve set the sourceUrl parameter to the file name we want to give the image when uploaded, this works around the “This item is a copy of…” issue when using the Copy web service.

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    June 29th, 2009stuartwhitefordHardware

    Recently, my Lacie Big Disk (500GB) died on me. It just stopped appearing as a drive on my PC and I tried it on other machines without success. Looking at some of the forum posts it appeared as if it was going to be one of two problems. Either one (or both) of the drives had failed or the internal controller had failed.

    Hoping that it was the controller I decided to get myself another one (eBay to the rescue). Taking both of them apart I swapped the drives from the bust one into the bought one, plugged it in and voila, it worked! So, I copied off all the stuff I wanted to keep then took it apart again.

    Now I had four 250GB drives sitting and I can only put two back into the Lacie enclosure. That wouldn’t do at all. I acquired myself a 3Ware RAID card (eBay again), albeit an older model as it had to support IDE drives not SATA. On arrival, off came the PC cover and in went the card and the four drives. I fired up the machine and opted for a RAID5 configuration giving me 750GB-ish, left it to format the drives and build the array for a few hours.

    Once in Windows I installed the drivers downloaded from the 3Ware support site. I had to force Vista to allow the unsigned drivers but other than that all went smoothly, and now I have 700GB+ fault tolerant drive in my PC. So if you’ve got an external hard drive, Lacie or otherwise, that’s broke and there’s a chance it’s not the disk itself then there just might be some of getting your data back and re-using the disk.

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