I have an application that shows a screen of image thumbnails, each image is around 80k and they are stored in a database. To keep response time reasonable, the appilcation displays a placeholder image when it first starts and later downloads the images from the server. I'm expecting to show around 40 images on the screen at once so that's my batch size. What's the best way to serve these images up to the client? I've got two options in mind.
Create an ADO.NET Data Service that exposes the Images database table to the client. The client can asynchronously request the images, one at a time, and display them as they come back from the server. I've implemented this solution and it seems to work Ok; the speed isn't great and I feel like I could utilize the Http pipe better by requesting maybe 3 images at a time.
Create an HttpModule on the server that looks for requests that look something like /Images/1.jpg and then reads the database and returns the requested data. On the client side I can have many Image objects whose source points to the virtual Urls on the server. My theory is that by just giving Silverlight many Urls to deal with it may be able to transfer the images more efficiently than my code in option 1.
Would either of these methods be more efficient or is there another technique for getting this done? Thanks!
I don't know if it's more efficient, but I've accomplished a very similar task using an HTTP Handler (ashx). The handler pulls the image in from the database based on the Parameters in the uri (image ID), and then Silverlight fetches them asynchronously by setting the Source property of an Image control to the URI of the handler with the specific ID that I want in the query string. The Image control, in turn, is inside of an ItemsControl which allows me to display multiple images.
We are doing something very similar, and we are just using an ASPX page to server them up with a query parameter of the image identifier. We are also caching the images, and the ASPX page will used the cached value if it exists. If not, we pull it from the data store, cache it, and send it down. It is working really well for us.
Have you looked at using Deep Zoom? It's very efficient about progressive image loading, and gives you a nicer user experience when the images are fully loaded.
Examples:
Hard Rock Memorabilia site
Deep Zoom Pix
Related
I want to upload the image in my website. The same image will be shown in another website. So this is the scenario where image is uploaded in one website and displayed in both website. These two websites are hosted in two different servers as well as they both have their own database.
I am using Angular JS, Entity Framework, Web API and SQL Server 2014 as backend for both of the website. Currently I am using ngFileUpload to upload the images. Please answer me on below questions:-
Should I upload the image in database(as nvarchar-max) or filesystem(FTP or local web server file system)? I read many articles and get to know that Database retrieval of image has affect on performance but it is more secured. However File System is easy in performance but complex on maintenance like back ups. So I am just not able to decide which to choose among these two as both have pros and cons. Which option will be more suitable to my requirement where same image will be displayed in both website. Please note that there can big images like upto 5 MB uploaded in the application but the number of images will not be huge as compare to any social networking or online shopping site.
How to create different size of images(thumbnail, medium, large etc) automatically upon uploading of image in website? Is there any tool or directive already available in Angular JS to achieve this?
I know my question is broad but I need suggestion to start with my requirements.
Please help.
I use the file system to host my images. If the image is displayed on someone's computer screen, they can use an image capturing software to copy it anyway. Also, while storing them to a database may be more secure, I don't need the extra overhead in my code where a simple url to retrieve the image will suffice.
As for resizing an image using Angular, check out these links:
https://www.scientiamobile.com/page/angular-image-resize
https://github.com/FBerthelot/angular-images-resizer
I could not think of a better title, Please suggest one.
I am planning to work on a large web application. It will take time to load the full application before application starts functioning.
Suppose its something like asana.com. If you have a link to the task and you open the link. It loads the application first and then shows the detail of the task.
Note: I have added another example in update 2
I want to do just the opposite. Suppose if I try to open the link directly. It should show me the tasks details first and then load the whole application in background.
What development strategy should I follow to implement such feature. Will angular be good for this? I have worked with angular for small projects and am capable of think in angular :)
I just wanted to be pointed in right direction.
Update 1:
I am using Apache2 PHP5 in backing as ReST API. I am thinking to change to GoLang http server. But that does not matter in this context :)
Update 2:
I have not yet started working on the application, but I know that its size is going to be big and its going to take time to load the application. This will be a javascript application, all the communication to web will be done mostly by API. APIs will be fast and it wont be slowing down the application. My main concern is the javascript library and the approach to the issue that I want to display the content of the page before the application is loaded and load the application in background.
As second example: https://chrome.google.com/webstore/detail/a-journey-through-middle/gjgkjeheegjnnmheaflhdocglkiegoni?utm_source=chrome-ntp-icon
If you open this link in chrome, it will load the application and then load the specific content in a popup. I want to load the content of the popup first and then load the application in background. How should I write my application to achieve that.
My suggestion (and I say this as I start to do similar vs. having proven it successful) would be to make some level of framework fairly static so that users get an almost instant response to the site loaded and then start the angular app with something like this
angular.bootstrap(document.getElementById("container"), ["app"])
Ref for the api - https://docs.angularjs.org/api/ng/function/angular.bootstrap
Ref for a demonstration of this - https://egghead.io/lessons/angularjs-angular-bootstrap-app-init
My expectation then is that you will be able to
Load your static elements quickly (which will just have placeholders for your content/material)
Access the data you want in the order you want to get it to present on the screen
Release any other part of the app you need to chrome it up/decorate or populate side items.
I am writing a program in C that acts like a proxy server in a Linux system: Client asks it for a web page,
it sends an HTTP GET Request to a distant server, and it gets the servers response (web page), which is saved in an .html file.
Here goes my problem: Most web sites got some references to images, so when i try to view the .html file proxy created, the images don't appear.
I have searched a lot, but found nothing..Is there a way to write some code to GET images too?
Thank you in advance
You're going to have to write code that parses the HTML file you get back and looks for image references (img tags), then queries the server for those image files. This is what web browsers are doing under the hood.
You have an additional problem though which is that the image references in the HTML file are to the original server. I'm assuming that since they don't load for you the server that returned the original HTML isn't available. In that case after you get each image file you will need to give it a name on the local filesystem and then alter the reference in the HTML (programmatically) to point to your new local image name.
So for example:
<img src='http://example.com/image1.png'>
would become
<img src='localImage1.png'>
If you're querying arbitrary websites then you'll also find that there are various other files you'll need to do the same with like CSS files and JavaScript files. In general its hard to mirror arbitrary web pages accurately - browsers have complex object models they use to interpret web pages because they have to deal with things like CSS and Javascript and you may need to be able to 'run' all that dynamic code to even be sure what files to download from the server (e.g. JavaScript including other JavaScript etc).
I have a WPF intranet app running in Trusted mode (local only).
I would like the users to be able to upload an image and attach it to an article on my newsletters section. I am having trouble deciding where these images will be stored.
Please provide me with your opinions.
At present I have a few ideas myself;
I could have an aspx page that runs parallel to this app, and run this inside a browser(I-frame). This page could then handle the upload and display of the image.
I could also, have the users copy directly to a network share.
It seems that there should be a more elegant sollution that I am not aware of.
Any ideas?
Don't force the solution towards ASPX just because you know how to do it there. It's unnatural to build a page, host browser to show that page etc, just so you could upload an image.
It's actually quite simpler to do it in a desktop client than on web page. You have a "Load File Dialog" - use that to get to the filepath the user wants to upload, and when you have that you can either:
copy it (inside your application) to your share,
or if you have a service - send it through some method call,
or you can even store it inside a database (recommended if the files are small)
There's really lots of options here... it depends if your client has connection to db, do you have service in between, etc...
What are the reasons that cause plugin analytics to use 1x1 img pixels to call their code? What permissions does this shortcut?
The server hosting the 1x1px image logs the request. This allows collecting statistics about who loads (and renders) the page with the image. Browsers in general allow cross origin in img tags.
Also, this allows javascript to be loaded from the same domain as the image.
Behind these image is a server-based script like php, python or so on which can get and log information about the visitor (visited page, referer, ip, ...) for the tracking-stats. The server will be able to get all information you can get on the serverside from a http-request. The benefits of this methods are that it works on nearly all browsers and devices. Its also lightweight because an 1x1 image will cause nearly zero bandwitch.
Its a common solution to track pageviews. To get more flexible, some alternative tracking-methods like pwiki don't even use javascript. They're inserting a tracking-pixel which also works when the user has javascript disabled or he is using some plugins which remove tracking-scripts.
It also works on emails so that the sender has information about which and how much users read for example a newsletter-mail. But nowadays nearly all deskto- and webclients are blocking images in emails by default to prevent these tracking-methods. Images will only be displayed when the user explicit allow this for a specific domain.