Annotation of loncom/javascriptlib/file_upload.js, revision 1.3

1.1       musolffc    1: /* 
                      2: The LearningOnline Network with CAPA
                      3: JavaScript functions handling file uploading
                      4: 
1.3     ! raeburn     5: $Id: file_upload.js,v 1.2 2019/08/07 16:08:17 raeburn Exp $
1.1       musolffc    6: 
                      7: Copyright Michigan State University Board of Trustees
                      8: 
                      9: This file is part of the LearningOnline Network with CAPA (LON-CAPA).
                     10: 
                     11: LON-CAPA is free software; you can redistribute it and/or modify
                     12: it under the terms of the GNU General Public License as published by
                     13: the Free Software Foundation; either version 2 of the License, or
                     14: (at your option) any later version.
                     15: 
                     16: LON-CAPA is distributed in the hope that it will be useful,
                     17: but WITHOUT ANY WARRANTY; without even the implied warranty of
                     18: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     19: GNU General Public License for more details.
                     20: 
                     21: You should have received a copy of the GNU General Public License
                     22: along with LON-CAPA; if not, write to the Free Software
                     23: Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
                     24: 
                     25: /home/httpd/html/adm/gpl.txt
                     26: 
                     27: http://www.lon-capa.org/
                     28: */
                     29: 
                     30: 
                     31: 
                     32: /*
1.3     ! raeburn    33: This function accepts a file input element and the universal part of the id 
        !            34: used for the hidden input element containing maximum upload size permitted.
        !            35: If the file(s) is too large, an alert is shown and the input is cleared.
1.1       musolffc   36: 
                     37: INPUT:
                     38:     fileInput -
1.2       raeburn    39:         <input type="file" class="LC_flUpload" />
                     40:         Using the class "LC_flUpload" is needed to use the event handlers below.
1.3     ! raeburn    41:     sizeItem -
        !            42:         <input type="hidden" id="PREFIXsizeItemSUFFIX" value="$maxsize" /> 
        !            43: 
        !            44:     The PREFIX is empty unless the resource is within a composite page.
        !            45:     
        !            46:     The SUFFIX is empty in cases where there will only ever be one file upload
        !            47:     input element in a web page. Otherwise it will contain a unique identifier,
        !            48:     so different maximum sizes can exist for each upload element.
        !            49:  
        !            50:     The value assigned to the hidden element is the maximum upload size in bytes.
        !            51: 
        !            52:     It is either calculated from quota and disk usage (e.g., upload to a course,
        !            53:     authoring space or portfolio space), or is set by a parameter (e.g., upload
        !            54:     to a dropbox, essayresponse or externalresponse item), or is hard-coded 
        !            55:     (e.g., upload to the help request form, or an attachment to a discussion post
        !            56:     or feedback message).
        !            57: 
1.1       musolffc   58: */
1.3     ! raeburn    59: 
        !            60: function checkUploadSize (fileInput,sizeItem) {
1.1       musolffc   61:     try {
1.3     ! raeburn    62:         var maxSize = getMaxSize(fileInput,sizeItem);
1.1       musolffc   63:         var fileSize = 0;
                     64:         if ('files' in fileInput) {
                     65:             if (fileInput.files.length > 0) {
                     66:                 for (var i = 0; i < fileInput.files.length; i++) {
                     67:                     fileSize += fileInput.files[i].size;
                     68:                 }
                     69:                 if (fileSize > maxSize) {
                     70:                     alert("File(s) too large to be attached");
                     71:                     clearFileInput(fileInput);
                     72:                 }
                     73:             }
1.3     ! raeburn    74:         } else { alert("no files selected for upload");}
1.1       musolffc   75:     } catch (e) { alert("Error is: " + e); }
                     76: }
                     77: 
                     78: /* 
                     79: This function clears the contents of a file input element.
                     80: 
                     81: INPUT:
                     82:     ctrl -
                     83:         <input type="file" />
                     84: */
                     85: function clearFileInput(ctrl) {
                     86:     try {
                     87:         ctrl.value = null;
1.3     ! raeburn    88:     } catch(e) { }
1.1       musolffc   89:     if (ctrl.value) {
                     90:         ctrl.parentNode.replaceChild(ctrl.cloneNode(true), ctrl);
                     91:     }
                     92: }
                     93: 
                     94: /*
1.3     ! raeburn    95: This function retrieves the allowed maximum file size for a file input element
        !            96: INPUT:
        !            97:     fileInput -
        !            98:         <input type="file" />
        !            99:     sizeItem -
        !           100:         <input type="hidden" id="PREFIXsizeItemSUFFIX" />
        !           101: 
        !           102:     For upload to a dropbox, essayresponse or externalresponse item,
        !           103:     the PREFIX and SUFFIX are extracted from the id of the file upload 
        !           104:     element, by separating the id into parts before and after HWFILE.
        !           105: 
        !           106:     The PREFIX is empty unless the resource is within a composite page.
        !           107: 
        !           108: */
        !           109: function getMaxSize (fileInput,sizeItem) {
        !           110:     var maxSize = 0;
        !           111:     var sizeId = sizeItem;
        !           112:     var uploadId;
        !           113:     try {
        !           114:         if ($(fileInput).hasClass("LC_hwkfile")) {
        !           115:             uploadId = $(fileInput).attr('id');
        !           116:             var re = /^(|\w*)HWFILE(.+)$/;
        !           117:             var found = uploadId.match(re);
        !           118:             if (found.length == 3) {
        !           119:                 sizeId = found[1]+sizeItem+'_'+found[2];
        !           120:             }
        !           121:         }
        !           122:         if ( $("#"+sizeId).length) {
        !           123:             if ( $("#"+sizeId).val() > 0) {
        !           124:                 maxSize = $("#"+sizeId).val();
        !           125:             }
        !           126:         }
        !           127:     }
        !           128:     catch(e) { }
        !           129:     return maxSize;
        !           130: }
        !           131: 
        !           132: /*
1.1       musolffc  133: This block adds event listeners to file upload elements.  It looks for input
1.2       raeburn   134: elements with class="LC_flUpload".
1.1       musolffc  135: 
1.2       raeburn   136:     <input type="file" class="LC_flUpload" />
1.1       musolffc  137: 
1.3     ! raeburn   138: It also looks for a hidden element with an id containing: "LC_free_space",
        !           139: which contains the maximum allowable upload size (bytes).
        !           140: 
        !           141:     <input type="hidden" id="*LC_free_space*" value="$free_space" />
1.1       musolffc  142: 
1.3     ! raeburn   143: The * before LC_free_space and the * after LC_free_space are PREFIX and SUFFIX.
1.1       musolffc  144: 
                    145: When the contents of the input element change, the function checkUploadSize()
                    146: checks if it is allowed based on size.
                    147: */
                    148: $( document ).ready(function() {
1.2       raeburn   149:     var upload_elements = $( ".LC_flUpload" );
1.1       musolffc  150:     for (var i=0; i<upload_elements.length; i++) {
1.3     ! raeburn   151:         if (getMaxSize(upload_elements[i],'LC_free_space')) {
        !           152:             upload_elements[i].addEventListener( "change", function(){
        !           153:                 checkUploadSize(this,'LC_free_space');
        !           154:             });
        !           155:         }
1.1       musolffc  156:     }
                    157: });

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