Captcha after several consecutive visits or actions - ruby-on-rails

I have a Rails application that has a search field that allows any visitor to search a database.
I'm hesitant to implement a Captcha because I'd like to keep the site clean and user-friendly.
However, I'd like to make it difficult for bots to try to harvest everything from the database by making tons of consecutive random queries. So I'm considering adding a Captcha that appears only if it looks like this is happening (e.g., the Captcha appears after a few bad searches).
Any suggestions for how to implement this? Should I try to use a session variable or keep track of IP addresses? Would I better off handling this issue at the server level (i.e., with an htaccess file)?

Consider using a honeypot. That means adding a form element that you hide with CSS. Bots cannot see that you've hidden the field and they will fill it in. Normal users will not fill it in.

Related

Requesting input on conceptual ideas for disguising browser history

I am working with a Domestic Violence support organisation to build a website and have been asked to provide a "Quick Exit" function.
The purpose is to enable the user to exit the site quickly without closing the browser. I have seen such buttons on similar sites and the normal scenario is that they simply cause a Google search page to be shown. (easy but doesn't hide history)
I am looking for ideas to improve on this function to hide/disguise the history stored in the browser as this is currently a fairly significant flaw with the Quick Exit buttons I've seen to date.
I had a concept but I am looking for input on either fleshing out my concept, or other alternative directions to consider.
My concept was to have two domains: let's call them dv-site.com and decoy-site.com. The former being the source of domestic violence support information and the latter being some random content, could be anything, lets just say weather information for the sake of the conversation.
If a user navigates directly to dv-site.com the server redirects to decoy-site.com but also attaches some session specific, or perhaps single use query string or similar.
decoy-site.com validates the query string and, if valid, loads dv-site.com within an iframe or something like that so from the users perspective they are just looking at dv-site.com, though the domain recorded in history is decoy-site.com.
Links within the iframe loaded site would similarly be redirected with the same or a new query string.
If a user was to click on the browser history and go directly to decoy-site.com it would not be able to validate the query string and would just load the decoy site like a normal site. i.e. just showing weather information that exist on that site.
Domestic violence is a serious systemic issue and I would love some input from anyone who has more technical knowledge than I do on fleshing out this concept.
Other aspects I am unsure of how to tackle;
ensuring that dv-site.com can get crawled and ranked by search engines, even though users are all redirected, as it is imperative that it appears in search results so it can be found
technical aspects of a redirect that does not appear in history.
I'm unsure if it's possible to do this without all content and engagement being attributed to the decoy-site..
For the redirect, I believe that HTTP redirects do not get stored in history. You can use a 302 redirect for that. HTTP has a set-cookie header that lets you record a cookie - coupled with the headers here, you can give the decoy site access without recording it in history. Then, delete the cookie.
As far as pagerank goes, you could add a line to robots.txt as described here (the last point) to force the bot to scrape using a query parameter. Then in the backend, return the dv site only if that parameter is passed, otherwise redirect. If the googlebot removes query params when publishing, it will work out. Otherwise, it might fail.
Best of luck.

Local storage on Rails

I've built a Rails app, basically a CRUD app for memos/notes.
A notes title must be unique. If a user enters a name already taken a warning message is shown prompting them to chose another.
My question is how to make this latency for this feedback as close to zero as possible. When creating a note little UX speed bumps like this will get annoying for user quickly.
Of course the main bottleneck is the network. Inspired by Meteor (and mini-mongo) I was thinking some kind of local storage could be a solution?
I.E. When app first loads, send ALL JSON to the client with ALL note titles. The app (front end is Angular JS) could check LocalStorage (or App Cache, Web SQL?) instead of incurring a network round trip. The feedback would be instant.
I've used LocalStorage in the past to augment an app, but in the scenario it'd really seriously depend on it. I'm not sure how confident I'd be building on something that user might not have. Also as the number of user Notes/Memos I have doubts how feasible it is to send a JSON object down the wire with ALL the note titles. That might get pretty big. On the other hand MeteorJS seems to do this with no probs.
Has anyone done something similar or have any pointers? Thanks!
I don't know how Meteor works here, but you're right that storing all note titles in localStorage is not a good idea. Actually, you don't need localStorage here, you can just put it in a JS array, because you need this data only once (when checking new note title).
I think, there could be 2 possible solutions:
You can change your business requirements and allow non-unique title. Is there really a necessity for titles to be unique?
You can verify note title when user submits form. In this case you can provide suggestions for users, so they not spend time guessing vacant title.
Or, if titles must be unique only within a user (two users can have same title for their notes), you can really load all note titles in JS array and check uniqueness while users types in a title.
Or you can send an AJAX request checking title uniqueness as soon as user finished typing the title. In this case you can win some seconds.
Or you can send an AJAX request as soon as user typed in 3 symbols. The request will return all titles that begin with these 3 symbols, so you don't need to load all the titles.

Persisting data in MVC for the duration of a users session

Apologies in advance as I'm sure this topic has no doubt been asked before but I couldn't find any post that answers my specific query.
Bearing in mind that I'm new to MVC this is where I have got to. I've got a project developed under VS 2010 using the MVC 3 framework. I've got a search page which consists of 6 fields and a nested model which itself holds around 3 fields.
I can successfully post all this data back to itself and the data is successfully passed as a model and back agian so the fields keep the data which the user has supplied.
Before I move on to actually using this search criteria on another view a thought hit me. I want to keep this search criteria, and possibly even the search results in memory for the duration of the users session.
The reasoning behind this is simply to save my users time by:
a) negating the need to keep re-inputting their search criteria regardless of how they enter or leave the search page
b) speed up the user experience by presenting the search results more quickly
The later isn't as important as the first requirement.
I've done some google searches and indeed had a look through this site on similar topics. From what I've read using sessions (which I would typically use if developing a PHP site) is a no no. From the reasons I've read as to why you shouldn't use sessions seem valid and I'm happy to go along with it.
But now I'm left in a place where I'm scratching my head wondering to myself what exactly is best practice to achieve this simple goal that could be applied to similar situations later down the line in the project.
I also looked at the OutputCache method and that didn't behave as I expected it to. In a test I set the timeout for 30 seconds. After submitting a search I clicked the link to my search page to see if the fields would auto-populate, they didn't. But then clicking the search button the values in the cache were retrieved. I thought I was making progress but when I tried to submit a new value the old value from the cache came back i.e. I couldn't actually change my search criteria with the cache enforced. So I've discounted this as an avenue to explore.
The last option seems to suggest the use of cookies as the most likely candidate, but rightly or wrongly I feel this isn't the best solution. I would have thought the MVC 3 design pattern would have an easier and recommended method of persisting values. I'm sure there is but I've just not discovered it yet.
I have started to use JQuery and again this has been mentioned but I'm not sure this is right direction to take either.
So in summary my question really comes down to what is considered by the wider community as best practice for persisting data in my situation. Effiency, scalability and resiliancy is paramount as I'll have a large global user base that will end up using this web app.
Thanks in advance!
Pete
I'd just use cookies. They're simple to use, you can persist them for as long as you want or have them expire when the users closes their browser, and it doesn't sound like you are storing anything sensitive in them.

Prevent bot from crawling certain areas of site

I don't know much about SEO and how web spiders work, so forgive my ignorance here. I'm creating a site (using ASP.NET-MVC) which has areas that displays information retrieved from the database. The data is unique to the user, so there's no real server-side output caching going on. However, since the data can contain things the user may not wish to have displayed from search engine results, I'd like to prevent any spiders from accessing the search results page. Are there any special actions I should take to ensure that the search result directory isn't crawled? Also, would a spider even crawl a page that's dynamically generated and would any actions preventing certain directories being search mess up my search engine rankings?
edit: I should add, I'm reading up on robots.txt protocol, but it relies on co-operation from the web crawler. However, I'd also like to prevent any data-mining users who will ignore the robots.txt file.
I appreciate any help!
You can prevent some malicious clients from hitting your server too heavily by implementing throttling on the server. "Sorry, your IP has made too many requests to this server in the past few minutes. Please try again later." In practice, though, assume that you can't stop a truly malicious user from bypassing any throttling mechanisms that you put in place.
Given that, here's the more important question:
Are you comfortable with the information that you're making available for all the world to see? Are your users comfortable with this?
If the answer to those questions is no, then you should be ensuring that only authorized users are able to see the sensitive information. If the information isn't particularly sensitive but you don't want clients crawling it, throttling is probably a good alternative. Is it even likely that you're going to be crawled anyway? If not, robots.txt should be just fine.
It seems like you have 2 issues.
Firstly a concern about certain data appearing in search results. The second about malicious or unscrupulous user harvesting user related data.
The first issue will be covered by appropriate use of a robots.txt file as all the big search engines honour this.
The second issue seems more to do with data privacy. The first question which immediately springs to mind is: If there is user information which people may not want displayed, why are you making it available at all?
What is the privacy policy for such data?
Do users have the ability to control what information is made available?
If the information is potentially sensitive but important to the system could it be restricted so it is only available to logged in users?
Check out the Robots exclusion standard. It's a text file that you put on your site that tells a bot what it can and can't index. You will also want to address what happens if a bot doesn't honour the robots.txt file.
robots.txt file as mentioned. If that is not enough then you can:
Block unknown useragents - hard to maintain, easy for a bot to forge a browser's (although most legitimate bots wont)
Block unknown IP addresses - not useful for a public site
Require logins
Throttle user connections - tricky to tune, you will still be disclosing information.
Perhaps by using a combination. Either way it is a trade off, if the public can browse to it, so can a bot. Be sure you don't block & alienate people in your attempts to block bots.
a few options:
force the user to login to view the content
add a CAPTCHA page before the content
embed content in Flash
load dynamically with JavaScript

Why would Google Search use client-side URL parameters?

Yesterday morning I noticed Google Search was using hash parameters:
http://www.google.com/#q=Client-side+URL+parameters
which seems to be the same as the more usual search (with search?q=Client-side+URL+parameters). (It seems they are no longer using it by default when doing a search using their form.)
Why would they do that?
More generally, I see hash parameters cropping up on a lot of web sites. Is it a good thing? Is it a hack? Is it a departure from REST principles? I'm wondering if I should use this technique in web applications, and when.
There's a discussion by the W3C of different use cases, but I don't see which one would apply to the example above. They also seem undecided about recommendations.
Google has many live experimental features that are turned on/off based on your preferences, location and other factors (probably random selection as well.) I'm pretty sure the one you mention is one of those as well.
What happens in the background when a hash is used instead of a query string parameter is that it queries the "real" URL (http://www.google.com/search?q=hello) using JavaScript, then it modifies the existing page with the content. This will appear much more responsive to the user since the page does not have to reload entirely. The reason for the hash is so that browser history and state is maintained. If you go to http://www.google.com/#q=hello you'll find that you actually get the search results for "hello" (even if your browser is really only requesting http://www.google.com/) With JavaScript turned off, it wouldn't work however, and you'd just get the Google front page.
Hashes are appearing more and more as dynamic web sites are becoming the norm. Hashes are maintained entirely on the client and therefore do not incur a server request when changed. This makes them excellent candidates for maintaining unique addresses to different states of the web application, while still being on the exact same page.
I have been using them myself more and more lately, and you can find one example here: http://blixt.org/js -- If you have a look at the "Hash" library on that page, you'll see my implementation of supporting hashes across browsers.
Here's a little guide for using hashes for storing state:
How?
Maintaining state in hashes implies that your application (I'll call it application since you generally only use hashes for state in more advanced web solutions) relies on JavaScript. Without JavaScript, the only function of hashes would be to tell the browser to find content somewhere on the page.
Once you have implemented some JavaScript to detect changes to the hash, the next step would be to parse the hash into meaningful data (just as you would with query string parameters.)
Why?
Once you've got the state in the hash, it can be modified by your code (or your user) to represent the current state in your application. There are many reasons for why you would want to do this.
One common case is when only a small part of a page changes based on a variable, and it would be inefficient to reload the entire page to reflect that change (Example: You've got a box with tabs. The active tab can be identified in the hash.)
Other cases are when you load content dynamically in JavaScript, and you want to tell the client what content to load (Example: http://beta.multifarce.com/#?state=7001, will take you to a specific point in the text adventure.)
When?
If you had a look at my "JavaScript realm" you'll see a border-line overkill case. I did it simply because I wanted to cram as much JavaScript dynamics into that page as possible. In a normal project I would be conservative about when to do this, and only do it when you will see positive changes in one or more of the following areas:
User interactivity
Usually the user won't see much difference, but the URLs can be confusing
Remember loading indicators! Loading content dynamically can be frustrating to the user if it takes time.
Responsiveness (time from one state to another)
Performance (bandwidth, server CPU)
No JavaScript?
Here comes a big deterrent. While you can safely rely on 99% of your users to have a browser capable of using your page with hashes for state, there are still many cases where you simply can't rely on this. Search engine crawlers, for example. While Google is constantly working to make their crawler work with the latest web technologies (did you know that they index Flash applications?), it still isn't a person and can't make sense of some things.
Basically, you're on a crossroads between compatability and user experience.
But you can always build a road inbetween, which of course requires more work. In less metaphorical terms: Implement both solutions so that there is a server-side URL for every client-side URL that outputs relevant content. For compatible clients it would redirect them to the hash URL. This way, Google can index "hard" URLs and when users click them, they get the dynamic state stuff!
Recently google also stopped serving direct links in search results offering instead redirects.
I believe both have to do with gathering usage statistics, what searches were performed by the same user, in what sequence, what of the search results the user has followed etc.
P.S. Now, that's interesting, direct links are back. I absolutely remember seeing there only redirects in the last couple of weeks. They are definitely experimenting with something.

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