Sakurai/pdf.js
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

[Chrome extension] Added JSDocs to pdfHandler.js

Browse Source 
And a small refactor to reduce the LOC in the onHeadersReceived
callback, to improve the readability of the code.
This commit is contained in:
Rob Wu 2013-07-01 18:38:41 +02:00
parent ba87d2fe11
commit efcf2aed6e
1 changed files with 77 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

118
extensions/chrome/pdfHandler.js
View File

@ -19,10 +19,21 @@ limitations under the License.
'use strict';
/**
* @param {Object} details First argument of the webRequest.onHeadersReceived
* event. The property "url" is read.
* @return {boolean} True if the PDF download was initiated by PDF.js
*/
function isPdfDownloadable(details) {
return details.url.indexOf('pdfjs.action=download') >= 0;
}
/**
* Insert the content script in a tab which renders the PDF viewer.
* @param {number} tabId ID of the tab used by the Chrome APIs.
* @param {string} url URL of the PDF file. Used to detect whether the viewer
* should be activated in a specific (i)frame.
*/
function insertPDFJSForTab(tabId, url) {
chrome.tabs.executeScript(tabId, {
file: 'insertviewer.js',
@ -35,6 +46,13 @@ function insertPDFJSForTab(tabId, url) {
});
});
}
/**
* Try to render the PDF viewer when (a frame within) a tab unloads.
* This indicates that a PDF file may be loading.
* @param {number} tabId ID of the tab used by the Chrome APIs.
* @param {string} url The URL of the pdf file.
*/
function activatePDFJSForTab(tabId, url) {
chrome.tabs.onUpdated.addListener(function listener(_tabId) {
if (tabId === _tabId) {
@ -44,60 +62,78 @@ function activatePDFJSForTab(tabId, url) {
});
}
/**
* Get the header from the list of headers for a given name.
* @param {Array} headers responseHeaders of webRequest.onHeadersReceived
* @return {undefined|{name: string, value: string}} The header, if found.
*/
function getHeaderFromHeaders(headers, headerName) {
for (var i=0; i<headers.length; ++i) {
var header = headers[i];
if (header.name.toLowerCase() === headerName) {
return header;
}
}
}
/**
* Check if the request is a PDF file.
* @param {Object} details First argument of the webRequest.onHeadersReceived
* event. The properties "responseHeaders" and "url"
* are read.
* @return {boolean} True if the resource is a PDF file.
*/
function isPdfFile(details) {
var header = getHeaderFromHeaders(details.responseHeaders, 'content-type');
if (header) {
var headerValue = header.value.toLowerCase().split(';',1)[0].trim();
return headerValue === 'application/pdf' ||
headerValue === 'application/octet-stream' &&
details.url.toLowerCase().indexOf('.pdf') > 0;
}
}
/**
* Takes a set of headers, and set "Content-Disposition: attachment".
* @param {Object} details First argument of the webRequest.onHeadersReceived
* event. The property "responseHeaders" is read and
* modified if needed.
* @return {Object|undefined} The return value for the onHeadersReceived event.
* Object with key "responseHeaders" if the headers
* have been modified, undefined otherwise.
*/
function getHeadersWithContentDispositionAttachment(details) {
var headers = details.responseHeaders;
var cdHeader = getHeaderFromHeaders(headers, 'content-disposition');
if (!cdHeader) {
cdHeader = {name: 'Content-Disposition'};
headers.push(cdHeader);
}
if (!/^attachment/i.test(cdHeader.value)) {
cdHeader.value = 'attachment' + cdHeader.value.replace(/^[^;]+/i, '');
return { responseHeaders: headers };
}
}
chrome.webRequest.onHeadersReceived.addListener(
function(details) {
// Check if the response is a PDF file
var isPDF = false;
var headers = details.responseHeaders;
var header, i;
var cdHeader;
if (!headers)
return;
for (i=0; i<headers.length; ++i) {
header = headers[i];
if (header.name.toLowerCase() == 'content-type') {
var headerValue = header.value.toLowerCase().split(';',1)[0].trim();
isPDF = headerValue === 'application/pdf' ||
headerValue === 'application/octet-stream' &&
details.url.toLowerCase().indexOf('.pdf') > 0;
break;
}
}
if (!isPDF)
if (!isPdfFile(details))
return;
if (isPdfDownloadable(details)) {
// Force download by ensuring that Content-Disposition: attachment is set
if (!cdHeader) {
for (; i<headers.length; ++i) {
header = headers[i];
if (header.name.toLowerCase() == 'content-disposition') {
cdHeader = header;
break;
}
}
}
if (!cdHeader) {
cdHeader = {name: 'Content-Disposition', value: ''};
headers.push(cdHeader);
}
if (cdHeader.value.toLowerCase().indexOf('attachment') === -1) {
cdHeader.value = 'attachment' + cdHeader.value.replace(/^[^;]+/i, '');
return {
responseHeaders: headers
};
}
return;
return getHeadersWithContentDispositionAttachment(details);
}
// Replace frame's content with the PDF viewer
// This approach maintains the friendly URL in the
// location bar
// Replace frame's content with the PDF viewer.
// This approach maintains the friendly URL in the location bar.
activatePDFJSForTab(details.tabId, details.url);
return {
responseHeaders: [
// Set Cache-Control header to avoid downloading a file twice
// NOTE: This does not behave as desired, Chrome's network stack is
// oblivious for Cache control header modifications.
{name:'Cache-Control',value:'max-age=600'},
// Temporary render response as XHTML.
// Since PDFs are never valid XHTML, the garbage is not going to be