I have been looking into various different APIs which can provide my the weather data I need in JSON format. A lot of these API's have certain limits such as: in order to get more requests per minute, you need to pay more money per month so that your app can make more API requests.
However, a lot of these API's also have free account which five you limited access to them.
So what I was thinking is, wouldn't it be possible for a developer to just make lots of different developer accounts with an API provider and then just make lots of different API keys?
That way, they wouldn't have to pay anything as they could stick with the free accounts. Whenever one of the API keys has reached the maximum daily request calls, the developer could just put a switch statement in their code which gets their software to use a different API key.
I see no reason why this wouldn't work from a technical point of view... but, is such a thing allowed?
Thanks, Dan.
This would technically be possible, and it happens.
It is also probably against the service's terms, a good reason for the service to ban all your sock puppet accounts, and perhaps even illegal.
If the service that offers the API has spent time and money implementing a per-developer limit for their API, they have almost certainly enforced that in their terms of service, and you would be wise to respect those.
(relevant xkcd)
Related
My goal is to synchronize a web-application with an internal database. The web-application has a public API, but in order to fully synchronize the two sources I would need to make around 2000 separate API calls every time. My instinct tells me that this is excessive and possibly irresponsible, but I lack the experience to know for sure.
In this particular case the web-application is Asana, but I've encountered similar situations before with other services. Is there any way to know if you're abusing a service through excessive API calls? I know I'm not going to DOS a company like Asana, but I can't shake the feeling that there must be a better way than making ~150k requests per day.
The only other option I can think of is to update the web-service only when I know there's been a change in the database, but I'll lose a lot of capability that way.
I apologize for the subjectivity of this question, but I'm really hoping that someone can explain if there's any kind of etiquette that's expected when using public APIs.
(I work at Asana)
This is an excellent question, or rather set of questions.
You are designing a system that will repeatedly make requests for every object. What will happen as the number of objects grows? Even if your initial request rate were reasonable, this would suffer problems with scalability. A more scalable solution is one that scales with the number of changes in the system. This will also grow over time, but much more slowly - the number of changes a single user can make per day is relatively constant, but the total number of objects they've created over time grows and grows. So my first piece of advice would be to avoid doing things this way, and instead find a way to detect changes and just act on those. It would be interesting to know why you feel you'll lose capability by taking this approach.
Now, I happen to know that the Asana API does not currently provide you with any friendly mechanism to just detect changes in the system. This is a commonly requested feature and we are looking into it, though I unfortunately cannot promise a delivery date. So you might be left with no choice but to poll our system for now.
As for being polite to the API, many service providers set limits on their API usage to prevent accidental or malicious use of the API from impacting the service to their other customers -- Asana is no exception. Sometimes these limits are published, other times not, and there is no standard limit: it all depends on the service. But it is very thoughtful of you to be curious about service limitations.
That said, 150k requests per day is, for the Asana API, kind of a lot. If all of our API users gave us that much traffic, we might be serving more requests per day than Google Web Search, and we're not quite that scalable yet. :) Technically, sometimes, we might handle requests at that volume from a single user.
If you must poll, try to poll on intervals like 15 minutes. But please do not poll your entire workspace on this time period; it's likely to be too much traffic/data. We're working on trying to provide you with a better solution.
If you do happen to make too many requests of the Asana API, you will get back HTTP status code 429 instead of your desired response; you can read more about that here (https://asana.com/developers/documentation/getting-started/errors).
Here's my issue. I have a site that provides some investing services, I pay for end of day data which is all I really need for my service but I feel its a bit odd when people check in during the day and it only displays yesterdays closing price. End of day is fine for my analytics but I want to display delayed quotes on my site.
According to the yahoo's YQL faq: If you use IP based authentication then you are limited to 1000 calls/day/IP, if my site grows I may exceed that but I was thinking of trying to push this request to the people browsing my site themselves since its extremely unlikely that the same IP will visit my site 1,000 times a day(my site itself has no use for this info). I would call a url from their browser, then parse the results so I can allow them to view it in the format of the sites template.
I'm new to web development so I'm wondering is it a common practice or a bad idea to have the users browser make the api call themselves?
It is not a bad idea at all:
You stretch up limitations this way;
Your server will respond faster (since it does not have to contact the api);
Your page will load faster because the initial response is smaller;
You can load the remaining data from the api in async manner while your UI is already responsive.
Generally speaking it is a great idea to talk with api's from the client. It's more dynamic, you spread traffic, more responsiveness etc...
The biggest downside I can think of is depending on the availability of other services. On the other hand your server(s) will be stressed less because of spreading the traffic.
Hope this helped a bit! Cheers!
I have a website that revolves around transactions between two users. Each user needs to agree to the same terms. If I want an API so other websites can implement this into their own website, then I want to make sure that the other websites cannot mess with the process by including more fields in between or things that are irrelevant to my application. Is this possible?
If I was to implement such a thing, I would allow other websites to use tokens/URLs/widgets that would link them to my website. So, for example, website X wants to use my service to agree user A and B on the same terms. Their page will have an embedded form/frame which would be generated from my website and user B will also receive an email with link to my website's page (or a page of website X with a form/frame generated from my server).
Consider how different sites use eBay to enable users to pay. You buy everything on the site but when you are paying, either you are taken to ebay page and come back after payment, or the website has a small form/frame that is directly linked to ebay.
But this is my solution, one way of doing it. Hope this helps.
It depends on how your API is implemented. It takes considerably more work, thought, and engineering to build an API that can literally take any kind of data or to build an API that can take additional, named, key/value pairs as fields.
If you have implemented your API in this manner, then it's quite possible that users of this API could use it to extend functionality or build something slightly different by passing in additional data.
However, if your API is built to where specific values must be passed and these fields are required, then it becomes much more difficult for your API to be used in a manner that differs from what you originally intended.
For example, Google has many different API's for different purposes, and each API has a very specific number of required parameters that a developer must use in order to make a successful HTTP request. While the goal of these API's are to allow developers to extend functionality, they do allow access to only very specific pieces of data.
Lastly, you can use authentication to prevent unauthorized access to your API. The specific implementation details depend largely on the platform you're working with as well as how the API will be used. For instance, if users must login to use services provided by your API, then a form of OAuth may suffice. However, if other servers will consume your API, then the authorization will have to take place in the HTTP headers.
For more information on API best practices, see 7 Rules of Thumb When You Build an API, and a slideshow from a Google Engineer titled How to Design a Good API and Why That Matters.
I've had a WCF Data service published for about 2 months. It's 100% been hacked already. I even noticed the service published on twitter!
Luckily my site was under development and the user entity was only about 80 beta testers.
Still this is a pretty big problem. With the power of E.F. Navigation properties anyone can easily write a script to download all my user data and my valuable domain data that no-one else has. I want to provide non-authenticated access and do things like:
Limit what columns get exposed (e.g. a users emails)
Limit number of requests possible per day (e.g. 10 per request host address)
Be notified when someone is misusing the service
Limit the results set and expand options on different entity sets
Stuff I haven't yet thought about
Does this make sense or should I drop WCF Data Services - which in theory sounded great, but now that I've got experience with them I'm wondering if they are just good for development and not production (they're kind of fatter than I was expecting).
Thoughts that go beyond my knowledge and suggestions here will be greatly appreciated.
Also posting any links to thorough blog post examples or video presentation that cover ground would be excellent!
I think you need to implement some authentication. There is no other way I can think of to "lock down" a web service. This is one of the advantages of WCF -- it makes implementing complex authentication easy.
On my WCF service, I require a UserContext object, simply comprised of two strings, username and password.
Every method on the service requires that context, and if I haven't added the username/password to the database, it denies the request.
This also makes it simple to track who is abusing the service, as you will have their username/password tied to every request.
You should also run it over SSL so other users' credentials will not be easily compromised.
1 - WCF Data Services currently doesn't allow you to easily filter columns on per request basis. You could have two EF models (one "public", and one "private") and expose them as two services. The public one accessible to anybody, the private one behind full auth.
2 - This you will have to implement yourself. But for this to work you need some way to identify the user. So it's pretty close to authentication (Even if it doesn't require password or something like that). There's a series of posts about auth over WCF Data Services here: http://blogs.msdn.com/b/astoriateam/archive/tags/authentication/
3 - If you can identify the user as per #2, you can for example count the number or frequence or requests he/she makes and setup a notification based on that. Again the techniques used for auth should provide you the right hooks.
4 - This is reasonably simple. WCF Data Service allows you to set hard limit on the size of the response (DataServiceConfiguration.MaxResultsPerCollection) or a soft limit, which means paging. Paging is usually better, since it limits the size of a single response but still allows clients to get all the data with multiple requests. This can be done through DataServiceConfiguration.SetEntitySetPageSize. The exand behavior can be limited by usage of DataServiceConfiguration.MaxExpandCount and MaxExpandDepth properties.
Some other possible techniques to use
Query interceptors (http://msdn.microsoft.com/en-us/library/dd744842.aspx) - this allows you to filter rows on per request bases. Typically used to limit rows based on the user making the request (note that this only allows you to filter rows, not columns).
Service operations - if you define a service operation which returns IQueryable the client can still compose queries on top of it, but it gives you the ability to filter the data before the query is applied. Or you can make certain pieces of information accessible only through service operations (not as easy to use and not queryable, but it gives you full control). (http://msdn.microsoft.com/en-us/library/cc668788.aspx)
I'm going to try to phrase this as a generic question.
A company runs a website that has a lot of valuable information on it. This information is queried from an internal private database. So technically, the information in the database is the valuable part.
If this company wished to develop an API that developers could use to access their database of valuable & useful information, what approach should the company take?
It's important to give developers what they need. But it is also important to keep competing websites from essentially using the API to steal everything and essentially steal all traffic from the company's website.
Is there was some way the API could be used in a way that drives traffic back to the original company's website somehow? Something that gives users a reason to keep going there.
This is a design consideration that my company is struggling with that I can imagine other web-based services have come across before.
Institute API keys - don't make it public. Maybe make the signup process more complex than "anyone with an e-mail address".
Rate limit the API based on keys. If you're running more than X requests a minute, you're likely mining the database.
Don't provide a "fetch everything" API. Make the users know something to get information on it. Don't reveal what you know.
I've seen a lot of companies giving out API keys and stating a TOS that all developers must adhere to. For example, any page that uses data from the API must include your logo and a link back to your website. If any developer is found breaking the rules, the API key can be cancelled and your data is safe again.
Who is meant to use the API?
A good general method of solving this problem is to limit access to the data to end users (rather than allow applications or developers at it). Provide applications and users with identification, each, and make sure that to access a subset of the data, a combination of both user and application key is required.
Following this pattern, each user will have access to a very limited subset of the data (presumably, the data that they require for their own specific use), and you can put measures in place to enforce this. Any attempts at data-mining will become obvious.
This type of approach meshes well with capability-type security models on the server side.