Comandos de Scripts: ¿Qué podemos hacer?
Al hilo de lo publicado en un artículo anterior sobre los comandos de script añadidos en la beta de Octubre"08, vamos a ver que cosas podemos hacer (y cuales no) utilizando estas instrucciones.
Comencemos por lo que no se puede hacer. Evidentemente, toda instrucción javascript que no esté dentro del estándar EMACScript no podrá ser ejecutada.
Esto incluye las derivaciones del estándar creadas por Microsoft para Internet Explorer o por Mozilla para el Firefox. Por ejemplo, no podremos hacer uso de ActiveX ni de cualquier comando que use el DOM (Document Object Model).
Y entonces que puedo hacer?
La idea fundamental de estos comandos es aprovecharse de la cantidad de código que existe en Internet con funciones muy útiles realizadas en javascript. En el artículo anterior vimos una sencilla función para calcular la letra del DNI, pero existen multitud de ellas más.
Por ejemplo, existen multitud de funciones que existen en php portadas a javascript. Un ejemplo es la función urlencode que podemos usar para codificar urls. Debemos coger la parte de dentro de la función y pasárselo a la instrucción de proceso "Script: Evaluar interprete", ya sea como fórmula o a través de una tabla con un campo objeto texto.
Este sería el código
return urlEncode(url);function urlEncode(str) {// http://kevin.vanzonneveld.net// + original by: Philip Petersonvar histogram = {}, histogram_r = {}, code = 0, tmp_arr = [];var ret = str.toString();var replacer = function(search, replace, str) {var tmp_arr = [];tmp_arr = str.split(search);return tmp_arr.join(replace);};// The histogram is identical to the one in urldecode.histogram['!'] = '%21';histogram['%20'] = '+';// Begin with encodeURIComponent, which most resembles PHP's encoding functionsret = encodeURIComponent(ret);for (search in histogram) {replace = histogram[search];ret = replacer(search, replace, ret) // Custom replace. No regexing}// Uppercase for full PHP compatibilityret.replace(/(\%([a-z0-9]{2}))/g, function(full, m1, m2) {return "%"+m2.toUpperCase();});return ret;}
Otras funciones interesantes que encontramos en el ciberespacio y que nos ahorraríamos realizar en Velneo son las relacionadas con funciones de seguridad. Por ejemplo la función que nos calcula el valor MD5 de una cadena.
return stringToMD5 + ' = ' + hex_md5(stringToMD5);/** A JavaScript implementation of the RSA Data Security, Inc. MD5 Message* Digest Algorithm, as defined in RFC 1321.* Version 2.1 Copyright (C) Paul Johnston 1999 - 2002.* Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet* Distributed under the BSD License* See http://pajhome.org.uk/crypt/md5 for more info.*//** Configurable variables. You may need to tweak these to be compatible with* the server-side, but the defaults work in most cases.*/var hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase */var b64pad = ""; /* base-64 pad character. "=" for strict RFC compliance */var chrsz = 8; /* bits per input character. 8 - ASCII; 16 - Unicode *//** These are the functions you'll usually want to call* They take string arguments and return either hex or base-64 encoded strings*/function hex_md5(s){ return binl2hex(core_md5(str2binl(s), s.length * chrsz));}function b64_md5(s){ return binl2b64(core_md5(str2binl(s), s.length * chrsz));}function str_md5(s){ return binl2str(core_md5(str2binl(s), s.length * chrsz));}function hex_hmac_md5(key, data) { return binl2hex(core_hmac_md5(key, data)); }function b64_hmac_md5(key, data) { return binl2b64(core_hmac_md5(key, data)); }function str_hmac_md5(key, data) { return binl2str(core_hmac_md5(key, data)); }/** Perform a simple self-test to see if the VM is working*/function md5_vm_test(){return hex_md5("abc") == "900150983cd24fb0d6963f7d28e17f72";}/** Calculate the MD5 of an array of little-endian words, and a bit length*/function core_md5(x, len){/* append padding */x[len >> 5] |= 0x80 << ((len) % 32);x[(((len + 64) >>> 9) << 4) + 14] = len;var a = 1732584193;var b = -271733879;var c = -1732584194;var d = 271733878;for(var i = 0; i < x.length; i += 16){var olda = a;var oldb = b;var oldc = c;var oldd = d;a = md5_ff(a, b, c, d, x[i+ 0], 7 , -680876936);d = md5_ff(d, a, b, c, x[i+ 1], 12, -389564586);c = md5_ff(c, d, a, b, x[i+ 2], 17, 606105819);b = md5_ff(b, c, d, a, x[i+ 3], 22, -1044525330);a = md5_ff(a, b, c, d, x[i+ 4], 7 , -176418897);d = md5_ff(d, a, b, c, x[i+ 5], 12, 1200080426);c = md5_ff(c, d, a, b, x[i+ 6], 17, -1473231341);b = md5_ff(b, c, d, a, x[i+ 7], 22, -45705983);a = md5_ff(a, b, c, d, x[i+ 8], 7 , 1770035416);d = md5_ff(d, a, b, c, x[i+ 9], 12, -1958414417);c = md5_ff(c, d, a, b, x[i+10], 17, -42063);b = md5_ff(b, c, d, a, x[i+11], 22, -1990404162);a = md5_ff(a, b, c, d, x[i+12], 7 , 1804603682);d = md5_ff(d, a, b, c, x[i+13], 12, -40341101);c = md5_ff(c, d, a, b, x[i+14], 17, -1502002290);b = md5_ff(b, c, d, a, x[i+15], 22, 1236535329);a = md5_gg(a, b, c, d, x[i+ 1], 5 , -165796510);d = md5_gg(d, a, b, c, x[i+ 6], 9 , -1069501632);c = md5_gg(c, d, a, b, x[i+11], 14, 643717713);b = md5_gg(b, c, d, a, x[i+ 0], 20, -373897302);a = md5_gg(a, b, c, d, x[i+ 5], 5 , -701558691);d = md5_gg(d, a, b, c, x[i+10], 9 , 38016083);c = md5_gg(c, d, a, b, x[i+15], 14, -660478335);b = md5_gg(b, c, d, a, x[i+ 4], 20, -405537848);a = md5_gg(a, b, c, d, x[i+ 9], 5 , 568446438);d = md5_gg(d, a, b, c, x[i+14], 9 , -1019803690);c = md5_gg(c, d, a, b, x[i+ 3], 14, -187363961);b = md5_gg(b, c, d, a, x[i+ 8], 20, 1163531501);a = md5_gg(a, b, c, d, x[i+13], 5 , -1444681467);d = md5_gg(d, a, b, c, x[i+ 2], 9 , -51403784);c = md5_gg(c, d, a, b, x[i+ 7], 14, 1735328473);b = md5_gg(b, c, d, a, x[i+12], 20, -1926607734);a = md5_hh(a, b, c, d, x[i+ 5], 4 , -378558);d = md5_hh(d, a, b, c, x[i+ 8], 11, -2022574463);c = md5_hh(c, d, a, b, x[i+11], 16, 1839030562);b = md5_hh(b, c, d, a, x[i+14], 23, -35309556);a = md5_hh(a, b, c, d, x[i+ 1], 4 , -1530992060);d = md5_hh(d, a, b, c, x[i+ 4], 11, 1272893353);c = md5_hh(c, d, a, b, x[i+ 7], 16, -155497632);b = md5_hh(b, c, d, a, x[i+10], 23, -1094730640);a = md5_hh(a, b, c, d, x[i+13], 4 , 681279174);d = md5_hh(d, a, b, c, x[i+ 0], 11, -358537222);c = md5_hh(c, d, a, b, x[i+ 3], 16, -722521979);b = md5_hh(b, c, d, a, x[i+ 6], 23, 76029189);a = md5_hh(a, b, c, d, x[i+ 9], 4 , -640364487);d = md5_hh(d, a, b, c, x[i+12], 11, -421815835);c = md5_hh(c, d, a, b, x[i+15], 16, 530742520);b = md5_hh(b, c, d, a, x[i+ 2], 23, -995338651);a = md5_ii(a, b, c, d, x[i+ 0], 6 , -198630844);d = md5_ii(d, a, b, c, x[i+ 7], 10, 1126891415);c = md5_ii(c, d, a, b, x[i+14], 15, -1416354905);b = md5_ii(b, c, d, a, x[i+ 5], 21, -57434055);a = md5_ii(a, b, c, d, x[i+12], 6 , 1700485571);d = md5_ii(d, a, b, c, x[i+ 3], 10, -1894986606);c = md5_ii(c, d, a, b, x[i+10], 15, -1051523);b = md5_ii(b, c, d, a, x[i+ 1], 21, -2054922799);a = md5_ii(a, b, c, d, x[i+ 8], 6 , 1873313359);d = md5_ii(d, a, b, c, x[i+15], 10, -30611744);c = md5_ii(c, d, a, b, x[i+ 6], 15, -1560198380);b = md5_ii(b, c, d, a, x[i+13], 21, 1309151649);a = md5_ii(a, b, c, d, x[i+ 4], 6 , -145523070);d = md5_ii(d, a, b, c, x[i+11], 10, -1120210379);c = md5_ii(c, d, a, b, x[i+ 2], 15, 718787259);b = md5_ii(b, c, d, a, x[i+ 9], 21, -343485551);a = safe_add(a, olda);b = safe_add(b, oldb);c = safe_add(c, oldc);d = safe_add(d, oldd);}return Array(a, b, c, d);}/** These functions implement the four basic operations the algorithm uses.*/function md5_cmn(q, a, b, x, s, t){return safe_add(bit_rol(safe_add(safe_add(a, q), safe_add(x, t)), s),b);}function md5_ff(a, b, c, d, x, s, t){return md5_cmn((b & c) | ((~b) & d), a, b, x, s, t);}function md5_gg(a, b, c, d, x, s, t){return md5_cmn((b & d) | (c & (~d)), a, b, x, s, t);}function md5_hh(a, b, c, d, x, s, t){return md5_cmn(b ^ c ^ d, a, b, x, s, t);}function md5_ii(a, b, c, d, x, s, t){return md5_cmn(c ^ (b | (~d)), a, b, x, s, t);}/** Calculate the HMAC-MD5, of a key and some data*/function core_hmac_md5(key, data){var bkey = str2binl(key);if(bkey.length > 16) bkey = core_md5(bkey, key.length * chrsz);var ipad = Array(16), opad = Array(16);for(var i = 0; i < 16; i++){ipad[i] = bkey[i] ^ 0x36363636;opad[i] = bkey[i] ^ 0x5C5C5C5C;}var hash = core_md5(ipad.concat(str2binl(data)), 512 + data.length * chrsz);return core_md5(opad.concat(hash), 512 + 128);}/** Add integers, wrapping at 2^32. This uses 16-bit operations internally* to work around bugs in some JS interpreters.*/function safe_add(x, y){var lsw = (x & 0xFFFF) + (y & 0xFFFF);var msw = (x >> 16) + (y >> 16) + (lsw >> 16);return (msw << 16) | (lsw & 0xFFFF);}/** Bitwise rotate a 32-bit number to the left.*/function bit_rol(num, cnt){return (num << cnt) | (num >>> (32 - cnt));}/** Convert a string to an array of little-endian words* If chrsz is ASCII, characters >255 have their hi-byte silently ignored.*/function str2binl(str){var bin = Array();var mask = (1 << chrsz) - 1;for(var i = 0; i < str.length * chrsz; i += chrsz)bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (i%32);return bin;}/** Convert an array of little-endian words to a string*/function binl2str(bin){var str = "";var mask = (1 << chrsz) - 1;for(var i = 0; i < bin.length * 32; i += chrsz)str += String.fromCharCode((bin[i>>5] >>> (i % 32)) & mask);return str;}/** Convert an array of little-endian words to a hex string.*/function binl2hex(binarray){var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";var str = "";for(var i = 0; i < binarray.length * 4; i++){str += hex_tab.charAt((binarray[i>>2] >> ((i%4)*8+4)) & 0xF) +hex_tab.charAt((binarray[i>>2] >> ((i%4)*8 )) & 0xF);}return str;}/** Convert an array of little-endian words to a base-64 string*/function binl2b64(binarray){var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";var str = "";for(var i = 0; i < binarray.length * 4; i += 3){var triplet = (((binarray[i >> 2] >> 8 * ( i %4)) & 0xFF) << 16)| (((binarray[i+1 >> 2] >> 8 * ((i+1)%4)) & 0xFF) << 8 )| ((binarray[i+2 >> 2] >> 8 * ((i+2)%4)) & 0xFF);for(var j = 0; j < 4; j++){if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);}}return str;}o el algoritmo SHA:return stringToSHA + " = " + hex_sha1(stringToSHA);/** A JavaScript implementation of the Secure Hash Algorithm, SHA-1, as defined* in FIPS PUB 180-1* Version 2.1a Copyright Paul Johnston 2000 - 2002.* Other contributors: Greg Holt, Andrew Kepert, Ydnar, Lostinet* Distributed under the BSD License* See http://pajhome.org.uk/crypt/md5 for details.*//** Configurable variables. You may need to tweak these to be compatible with* the server-side, but the defaults work in most cases.*/var hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase */var b64pad = ""; /* base-64 pad character. "=" for strict RFC compliance */var chrsz = 8; /* bits per input character. 8 - ASCII; 16 - Unicode *//** These are the functions you'll usually want to call* They take string arguments and return either hex or base-64 encoded strings*/function hex_sha1(s){return binb2hex(core_sha1(str2binb(s),s.length * chrsz));}function b64_sha1(s){return binb2b64(core_sha1(str2binb(s),s.length * chrsz));}function str_sha1(s){return binb2str(core_sha1(str2binb(s),s.length * chrsz));}function hex_hmac_sha1(key, data){ return binb2hex(core_hmac_sha1(key, data));}function b64_hmac_sha1(key, data){ return binb2b64(core_hmac_sha1(key, data));}function str_hmac_sha1(key, data){ return binb2str(core_hmac_sha1(key, data));}/** Perform a simple self-test to see if the VM is working*/function sha1_vm_test(){return hex_sha1("abc") == "a9993e364706816aba3e25717850c26c9cd0d89d";}/** Calculate the SHA-1 of an array of big-endian words, and a bit length*/function core_sha1(x, len){/* append padding */x[len >> 5] |= 0x80 << (24 - len % 32);x[((len + 64 >> 9) << 4) + 15] = len;var w = Array(80);var a = 1732584193;var b = -271733879;var c = -1732584194;var d = 271733878;var e = -1009589776;for(var i = 0; i < x.length; i += 16){var olda = a;var oldb = b;var oldc = c;var oldd = d;var olde = e;for(var j = 0; j < 80; j++){if(j < 16) w[j] = x[i + j];else w[j] = rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);var t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)),safe_add(safe_add(e, w[j]), sha1_kt(j)));e = d;d = c;c = rol(b, 30);b = a;a = t;}a = safe_add(a, olda);b = safe_add(b, oldb);c = safe_add(c, oldc);d = safe_add(d, oldd);e = safe_add(e, olde);}return Array(a, b, c, d, e);}/** Perform the appropriate triplet combination function for the current* iteration*/function sha1_ft(t, b, c, d){if(t < 20) return (b & c) | ((~b) & d);if(t < 40) return b ^ c ^ d;if(t < 60) return (b & c) | (b & d) | (c & d);return b ^ c ^ d;}/** Determine the appropriate additive constant for the current iteration*/function sha1_kt(t){return (t < 20) ? 1518500249 : (t < 40) ? 1859775393 :(t < 60) ? -1894007588 : -899497514;}/** Calculate the HMAC-SHA1 of a key and some data*/function core_hmac_sha1(key, data){var bkey = str2binb(key);if(bkey.length > 16) bkey = core_sha1(bkey, key.length * chrsz);var ipad = Array(16), opad = Array(16);for(var i = 0; i < 16; i++){ipad[i] = bkey[i] ^ 0x36363636;opad[i] = bkey[i] ^ 0x5C5C5C5C;}var hash = core_sha1(ipad.concat(str2binb(data)), 512 + data.length * chrsz);return core_sha1(opad.concat(hash), 512 + 160);}/** Add integers, wrapping at 2^32. This uses 16-bit operations internally* to work around bugs in some JS interpreters.*/function safe_add(x, y){var lsw = (x & 0xFFFF) + (y & 0xFFFF);var msw = (x >> 16) + (y >> 16) + (lsw >> 16);return (msw << 16) | (lsw & 0xFFFF);}/** Bitwise rotate a 32-bit number to the left.*/function rol(num, cnt){return (num << cnt) | (num >>> (32 - cnt));}/** Convert an 8-bit or 16-bit string to an array of big-endian words* In 8-bit function, characters >255 have their hi-byte silently ignored.*/function str2binb(str){var bin = Array();var mask = (1 << chrsz) - 1;for(var i = 0; i < str.length * chrsz; i += chrsz)bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (32 - chrsz - i%32);return bin;}/** Convert an array of big-endian words to a string*/function binb2str(bin){var str = "";var mask = (1 << chrsz) - 1;for(var i = 0; i < bin.length * 32; i += chrsz)str += String.fromCharCode((bin[i>>5] >>> (32 - chrsz - i%32)) & mask);return str;}/** Convert an array of big-endian words to a hex string.*/function binb2hex(binarray){var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";var str = "";for(var i = 0; i < binarray.length * 4; i++){str += hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8+4)) & 0xF) +hex_tab.charAt((binarray[i>>2] >> ((3 - i%4)*8 )) & 0xF);}return str;}/** Convert an array of big-endian words to a base-64 string*/function binb2b64(binarray){var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";var str = "";for(var i = 0; i < binarray.length * 4; i += 3){var triplet = (((binarray[i >> 2] >> 8 * (3 - i %4)) & 0xFF) << 16)| (((binarray[i+1 >> 2] >> 8 * (3 - (i+1)%4)) & 0xFF) << 8 )| ((binarray[i+2 >> 2] >> 8 * (3 - (i+2)%4)) & 0xFF);for(var j = 0; j < 4; j++){if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);}}return str;}
Puedes probar estos scripts en la aplicación vScriptRunner que está en nuestro catálogo de aplicaciones. Simplemente añades un nuevo registro en la tabla de scripts, pegas el código que figura arriba, creas la variable (p.e. en el primer script la variable sería url), le das un valor y a continuación ejecutas el script.
Las posibilidades son infinitas y podemos contar con un gran repositorio de funciones útiles obtenidas de la ingente cantidad de catálogos que existen en la red.
¿Se te ocurre alguna utilidad más a parte de la expuesta en este artículo? ¿Conoces alguna función interesante que quieras aportar a la comunidad?
Ahora es el momento.
