We have a PHP page that uses iframes as created by the Google Maps link feature. The Google Map being displayed is a KML file from our web site.
http://www.slocleanair.org/air/AirForcasting_map3.php shows the two maps.
The URL displayed is created via PHP script when the page loads so that the link points to 'todays' forecast. The six days of forecasts are uploaded weekdays and the KML filenames include the date. We add a &time=xxxx parameter to the URL to make it unique for each page load. This is a very low volume application.
Our problem is if we bungle today's forecast and need to upload a new version of the KML we cannot see the new version. It appears that the time parameter is not busting cache as we would like. It does not appear that local cache is being used as the problem appears across browsers and PCs.
Is the map being cached by Google? If so how can we force a refresh short of renaming the file?
I suppose our web server could be caching as well - if so might there be a generic way to force our server to refresh its cache? If this is even a possibility I can contact them for specific help - is this cache point even possible?
Ideas? Thanks in advance!
Related
Lets say, one visited a Website, which loaded a js-module.
This module loaded some information into a form and the chrome browser displayed it.
Is it anyhow possible to restore this information (i.e. via the browser cache) and view it?
What I've tried so far:
View Source of Web-Page in Chrome, but i did not record the communication, so no data here
installed "ChromeCacheView v2.21 - Cache viewer for Google Chrome Web browser" and viewed the Files with Dates which correspond to the concerning session time
Regarding the second point: I can only view the js-files unfortunately.
Yes, but it depends on what device you are on. If you are on the computer, go into your google history and find the website you need. Then, you can copy the link and save it somewhere else.
Also, if you don't know how to get into your history, click control h.
So, I am working on a project(building a chrome extension) that requires data to be stored on the local machine of the user. The size of data is quite large hence I thought of using IndexDB for this purpose.
My Question is whether is it possible to connect a chrome extension with IndexDB and query the database at the same time??
If Yes, Then how can I integrate them. In which file(popup.js or background.js or any other file) should I include the source code for creating the database.
I want the code for creating the database to run only once. After that I only want to update or delete data only.
If No, then is there any other way to achieve this?? The data is large hence I cannot store data in local storage.
Any paper, online material, advice or method from chrome developers or any other valid site would be helpful. Any example would help me alot.
Thankyou.
You can store tons of data in any HTML5 storage (including IndexedDB or localStorage) and chrome.storage.local with "unlimitedStorage" permission.
HTML5 data is stored per URL origin and each extension has its own one that looks like chrome-extension://id where id is a 32-character string that is the extension's id. In Firefox the origin looks like moz-extension://id.
Extension's own HTML5 storage:
can be accessed in any extension page (popup, options, background) just like you would do it in a web page, there are no differences.
cannot be accessed in a content script as it runs in a web page and thus can only access HTML5 storage of the web page's URL origin.
chrome.storage.local can be accessed in any extension page and in a content script.
No need for special event to create/upgrade your IndexedDB storage - it'll happen automatically if needed - simply open it as shown in the documentation whenever you need to access it and your onupgradeneeded callback will be invoked in case there was no DB or it was outdated.
Use a wrapper library for IndexedDB that provides a simplified syntax. Some are listed in the documentation, but you can probably find better ones yourself.
I'm making a webapp for members of my caving club to search through and view cave survey note PDFs. It works fine, and I got the AppCache working for the web version of it.
However, since the PDFs are quite large and slow to download, and many members have the PDFs on their local machines from the same SVN the website gets them from, it would be ideal for them to be able to use a page with links to a local SVN folder of their choosing.
The design goals:
The site displays links to PDF files on the local filesystem
Whenever I add features to the site, users get them automatically the next time they open the page and they're connected to the internet
But after the first time they open the page, the site works offline.
Sadly web browsers don't appear to support this useful combination of design goals at once.
I can satisfy #1 by having users download a copy of the site, add their local SVN path in a JS, and open their local copy in the browser, so that file:/// links work.
I can satisfy #2 by having absolute links to JS bundles on the server.
I can satisfy #3 by using the AppCache.
I thought I could get clever by having the copy of the page on the local file system have <html manifest="https://myserver.com/myapp.appcache">, but unfortunately Chrome doesn't seem to allow a local file to use an app cache manifest hosted on a server, for seemingly no good reason to me.
Does anyone know of another way I could satisfy all 3 goals?
Perhaps there's some simple program/config I could give my friends that would intercept web requests to https://myserver.com/some/folder and instead serve them out of a folder on their local file system?
Andy,
I know this post is a bit old but came across it looking for something else related to AppCache. My understanding it that the html page and the manifest must reside in the same domain for it to work. So I think you need to modify your design:
Create a JavaScript function that acts as a setting for the user to enter the path to their local copy of the PDF's. Store this information in localstorage.
Create a html template page for the document links.
Create a JavaScript function that populates the html template page with any documents and links the user enters.
This way, the users visit your application online and it uses appcache to store itself and the JS files for offline use. To access the PDF's, the user clicks a settings button that launches a page to collect path information and saves the information in localstorage. The users can then access the template page which will populate with the documents they entered.
Here is a good intro to localstorage: [http://www.smashingmagazine.com/2010/10/local-storage-and-how-to-use-it/]
I've developed an extension for Google Chrome that HEAVILY relies on Google Drive API (the extension is LBTimer, available in Google Chrome web store), to store data in the appfolder, using XMLHttpRequests
Since May, 13th 2015 I'm finding a problem when using the list method.
If I programmatically create a file in the appfolder, I receive the response: 200 OK and the file created. If then I use the list method to list the files in the appfolder, the file just created is not listed. It happened with several files yesterday. This morning, the files were listed normally, but with any file I create today it happens the same (correctly created but not listed).
Three screens follow: the 1st one is creating a test file in the appfolder using the extension's code. the image shows the server response (200 OK, file created). The second screen shows the list request (list all files whose title contains 'test', it should include the file just created). The third screen shows the response from the server (an empty items list).
There is a way to get them listed: If I create a file, it returns (among other data) the file Id. If I make a simple GET request for that Id, then it is listed from then on.
All other methods are working as expected (as usual), but the list method is giving me this problem since yesterday. Since there was no change in the extension's code, I assume there must have been a change in the API code.
Apparently, it was a caching issue in Google Drive, which has been resolved as of May 15th 2015: Google Drive developers community post
Yes, I noticed the same issue from today. I'm using Google Drive Java API to create files in hidden Application data folder (appfolder). Files are created correctly, but "Hidden data size" i 0. I noticed that my files appears after few hours! I reported this issue to Google several hours ago by Google Developers Console, but the issue still occurs. I think more users should do this to get their attention to this critical issue.
I've developed an iPad web app that uses the appcache. It's not intended to be a fully offline app but I use the appcache to store large image files so that they're not sent over 3G. Problem is when the manifest is updated the appcache updates whether the iPad is on wifi or 3G, which could be expensive.
Is it possible to have the user decide if the appcache can be updated or not? From what I've seen, this isn't possible, it all happens automatically, you just get events. But perhaps there's some trickery like writing the manifest on the fly or similar.
Using PHP on the server side if that helps. Thanks.
Connection Type: Theory & Future
There is a draft spec of Network Information API on W3C that provides the information of the connection type (ethernet wifi 2g 3g 4g etc.), but it hasn't been implemented on any browser yet apart from:
the stock Android browser on Android 2.2+ (not the Google Chrome browser)
navigator.connection.type // Based on W3C draft, (Implemented on stock Android browser)
and PhoneGap which is not exactly a browser
navigator.network.connection.type // on PhoneGap
Having that information in the future you could detect if the user has cellular data, then temporarily remove the src of the images and ask the user through a confirmation dialog.
You will also probably have to cancel the app cache update using:
window.applicationCache.abort() (documentation)
Reality
Unfortunately, the Net Info API is not available (at least not widespread) at the moment, but certainly will help in the future.
Long shot
There is a database that includes network speed (DIAL = dial up, DSL = broadband/cable, COMP = company/T1), but I haven't used it and I doubt it will help.
Dynamic App Cache
While checking into this, I tried to generate the html tag along with the manifest declaration on the fly, in order to combine it with the Network Info API but the AppCache manifest is loaded before javascript execution and is not affected afterwards.
So altering the manifest file on the fly through Javascript is not possible and data URI is not an option.
Alternative solution
HTML5 application cache is an untamed beast at the moment and there are talks to improve it. Until it changes to support more complex configurations (bandwidth level flag would be awesome), you could change perspective on the solution, although App Cache may be the best you have at the moment.
Depending on how big your images are you could rely on the normal browser cache. You could combine localStorage and far-future expiration HTTP headers. LocalStorage in order to keep track of the loaded/cached images.
First add a far in the future date for expiration on your images HTTP headers
On page load, remove all src from imgs
Loop the images and check localStorage if each image was loaded in the past
If there are images that were not loaded in the past, display a dialog confirming for the downloading of those images
If the image was loaded in the past, then put back the src on the img
For every image that is downloaded, save its URL on localStorage
I don't know what the status of indexedDB is on the iPad, but this could be an alternative solution.
In short: Indexeddb is a clientside database. Data is stored in object stores which are key/value pairs. The maximum storage capacity is in theory the maximum of your disk space. For more information about indexeddb:
Specification
My blog
What you could do with the indexeddb:
When someone navigates to a page:
Check every image tag if it is present in the indexeddb
if present
Get the image from the indexeddb and put it in the image tag
if not present
Download it
store it in the indexeddb
put the image in the image tag.
As extra (in the future) you can do as discribed by Sev: check the connetion type and only download the image when working on a fast internet connection.
I have 'invented' a working solution developing a webapp on the iPad (iOS 6.0.x) that may answer your question.
The idea is first to check if a localstorage variable is set/defined or not yet (I use the title of the page, thus the webapp name.)
If this localstorage variable exists, then assume (in webapp sandbox context) that its the first time the app is being run. At this point I populate a UUID in conjunction with $PHP_SESSION($uuid) to avoid 'cross app contamination' in server-side PHP land.
In addition to this I have a dynamic manifest.appcache.php which includes in the CACHE section a list of files to add to the manifest. Thus;
<?
echo $manifest_file_list[0]."\n";
?>
Using the JS appcache manifest event listeners I then monitor the progress to something like $('#manifestappcache').html(result);