5 ms·

Sammy.js, CouchDB, and the new web architecture

81 points by thisduck 17y ago

gcv 17y ago
I like this idea quite a bit. No application server means less maintenance and less administrative overhead. Of course, it also means that the newly-empowered database has to scale out just as easily as an application server. For starters, request authentication becomes the responsibility of the database, and that could mean heavy volume.
mcav 17y ago
Good, except that you still have to deal with authentication, authorization, and other security aspects of a server-side component. Server-side code won't go away no matter how fat the client gets.
- Periodic 17y ago
  In this case it will just move into the database. You'll have to start writing procedures and rules in the database instead of in your web framework and only expose those instead having only trusted code interact with the DB.
  - mechanical_fish 17y ago
    You'll have to start writing procedures and rules in the database instead of in your web framework This will not fool anyone. You can't fold the business logic into the database and then pretend that you've eliminated the business-logic layer on the server. It's still there. You've just driven it into hiding.
    - Periodic 17y ago
      Exactly. I don't think there is an equivalence between server code and client code. There are some things you just can't trust the client to do, so there will always have to be server code to do it. Whether that code is in a web server, a framework, a database, it doesn't matter. Someone has to write it. However, I could see some of the code, such as the code that actually builds the page the users sees, being pushed into the browser. But then, don't we already have that with XML and XSLT (or whatever?)
  - voidfiles 17y ago
    couchDB folks are trying to create auth in client, they haven't succeeded yet, the crypto algorithms are a bit taxing on the browser, but they are trying.
chime 17y ago
Honest question: How would one go about implementing authentication/security into such a setup? Maybe it could work for 1-writer, many reader apps (blogs) but how do you handle user signups, accounts, and security with this?
- thisduck 17y ago
  I think CouchDB might have built-in authentication coming soon, but I'm not sure about that. There's always the option of using HTTP authentication.
  - akeefer 17y ago
    Is that really good enough, though? For example, suppose that I write a blogging platform, and I want to ensure that a user can only query their own blog entries. How would I do that if the query is coming from the client (which always has to be untrusted) directly to the database? What prevents someone from rewriting the js client side so that it queries blog posts from other users? Or to prevent it from just sucking back all the blog posts in the DB and essentially DOSing the whole server? Doing per-user security directly in the DB with simple CRUD permissions per table would be enough of a headache, but most applications eventually require finer-grained security than that, and for performance reasons you also don't want a client to be able to execute just any arbitrary query. It seems like this is pretty close to same trap a lot of people fall into of only enforcing data validation client-side, or only enforcing things like view permissions client-side (by not rendering links), which leaves all sorts of holes open.
    - Periodic 17y ago
      I kept hoping the next paragraph would address this, but it didn't. It's cool and all, but it sounds like you're still going to basically need a server stack there to enforce permissions and some logic and consistency things. For example, say users have some private data. What stops me from modifying the javascript to insert a record that points to someone else's email address in my record? Unless the database can see this and prevent it I might then be looking at or even able to change someone else's email on their account. It can get very hairy if you don't have full control over the database interaction because you have to start guarding against arbitrary database operations.
moe 17y ago
Yes, history keeps repeating. It's hilarious to watch these kids reinvent, well, everything, over and over. So, here we have the return of the fat client, episode 20. And as with all the other episodes the standard question remains: If you're going fat-client then why on earth stick to a platform as horrible as HTML/JS?
- rcoder 17y ago
  The reasons to stick with DHTML/JS as a "thick client" development platform are simple: decent, free development tools, the ability to interpose proxies and application middleware between the client and server transparently, and a very, very large install base for the client runtime. That being said, I share much of your amusement at/disdain for the attitude of "OMG, look at this brand new thing I have made that is completely different from all those old things!"
  - moe 17y ago
    I'm not sure about these reasons. decent, free development tools Well, you can have these for any mature platform. Be it QT, Flex or even Java. I'm not sure what's more decent about the HTML toolchain. The often cited FireBug is, to me, merely an emergency bandaid that makes development at least possible but still far from enjoyable. the ability to interpose proxies and application middleware between the client and server transparently There's nothing stopping any fat-client to speak HTTP. You don't need to a browser for that. and a very, very large install base for the client runtime. I'd say installation base is a red herring when talking about cross-platform apps but I'll give you that "instant-on" is an argument. For that I'd point to Air, which can run hybrid in and outside the browser. I'm not arguing that HTML doesn't have it's place, mind you. But the extent to which it is abused nowadays is absurd.
    - shabda 17y ago
      > and a very, very large install base for the client runtime. You are underetimating this. For evrything else, (air, java, Qt, C#) I have to start a new app. My firefox is always on.
n8agrin 17y ago
With the power of CouchApp and _attachments, the javascript and HTML files needed to serve the application are served directly out of the database. That statement kind of troubles me. It shows that you're really just offloading all of the work from a normal app server to the data storage layer. From a "Mom look what I can do!" perspective this is cool, but, again, you're not eliminating your app server. Couchdb allows this because it uses HTTP as it's communication protocol, but one could do the same with MySQL, via an HTTP communication frontend, which sounds a lot like what Rails, Django, etc effectively are with some optimizations to make other non-data-storage operations faster.
richcollins 17y ago
When all you have is a hammer ... jQuery is not a good architecture for a full client application. jQuery is meant for flipping some dom attributes here and there. It does a poor job of modeling the UI state. Sinatra is also a poor architecture choice for the client since the client has persistent state. We already have a well designed client architecture. It's called Cocoa and its implemented in the browser as Cappuccino.
- jherdman 17y ago
  Interesting point. I tend to agree with you. I find myself hesitant about putting my business logic essentially on the front-end. With the current model we can hide some of the "secret sauce" that makes our applications unique on the server end. With something like Cappuccino (or Sammy.js, etc), how do we keep our secret sauce secret?
  - shykes 17y ago
    > I find myself hesitant about putting > my business logic essentially on the front-end Leave the business logic on the server where it belongs - but hide it behind a REST API, and leave the rendering to the browser. I think that's the core argument, if you omit the "CouchDB as an app server" part (which is orthogonal).
    - ams6110 17y ago
      This was exactly the approach I took with an app about 4 - 5 years ago. Back then XML not JSON was the data transport format, but I kept it lightweight. The UI was built in the browser using XSLT to generate HTML. Additional transforms tied to UI events allowed filtering, sorting, etc. all on the client. IE, for all its other flaws, actually supported this much better than any other browser at that time and we were developing in an IE-only environment. Business logic was on the server in stored procedures, which were exposed in a simple web service api so they could be called directly by the browser script logic. This also made it very testable because the stored procedures could be invoked by testing scripts that did not depend on the presence of any middle tier or UI at all. It also would have been a simple matter to build other client front-ends, as long a platform could work with XML and HTTP it could in theory be a client. The XSLT to render the UI from XML could get a bit verbose but despite that it turned out to be a very productive way to work. The downsides at the time were that IE was slow to render when you injected the HTML output of the transforms into the body.innerHTML property; this became noticeable if the generated page was large, but on the plus side this was a constraint against developing overly-complex pages.
dolinsky 17y ago
This might work for the simplest of sites like some have pointed out (e.g. a blog) but what I can't accept is having application logic on the frontend. Beyond authentication (let's say OAuth et all solve that issue down the road), one of the benefits of having serverside code is that when it comes down to it, you as a developer don't care if the user messes with the frontend (exposed) business logic (usually form validation of some type) because you're always checking it again / cleansing it on the serverside. That's the tip of the iceberg...ranking algorithms, limits on certain activities (rules in general). Now, that serverside code can be javascript serverd on something akin to 10gen if javascript is their tool of choice, but exposing any of those to the user so that they may edit them without any secondary sanity check is unacceptable.
sunkencity 17y ago
learning JavaScript & prototype i wrote a Twitter clone around this idea. I put up a number of textfiles in different user directories, and turned apaches directory listings on, and voilà a very basic restful interface. I also added post somehow, maybe a php script. The client-side script could read who to follow from the server and by itself performed the task of assembling the timeline which was the CPU and IO extensive task that twitter had problems scaling with. Not sure the extra bandwidth cost of performing this client side would be worth it, but there's almost no logic at all server side so there's not much scaling of processor power at least. Programming with prototype was fun, but then I found jQuery...
cmelbye 17y ago
Is anyone actually using this architecture?
californiaguy2 17y ago
Stop the madness. Just stop it.
tzury 17y ago
How on earth are these guys going to prevent a user from reading all the credit cards from that couch-db via its json interface?

81 points by thisduck 17y ago

gcv 17y ago

I like this idea quite a bit. No application server means less maintenance and less administrative overhead. Of course, it also means that the newly-empowered database has to scale out just as easily as an application server. For starters, request authentication becomes the responsibility of the database, and that could mean heavy volume.

mcav 17y ago

Good, except that you still have to deal with authentication, authorization, and other security aspects of a server-side component. Server-side code won't go away no matter how fat the client gets.

Periodic 17y ago
In this case it will just move into the database. You'll have to start writing procedures and rules in the database instead of in your web framework and only expose those instead having only trusted code interact with the DB.
- mechanical_fish 17y ago
  You'll have to start writing procedures and rules in the database instead of in your web framework This will not fool anyone. You can't fold the business logic into the database and then pretend that you've eliminated the business-logic layer on the server. It's still there. You've just driven it into hiding.
  - Periodic 17y ago
    Exactly. I don't think there is an equivalence between server code and client code. There are some things you just can't trust the client to do, so there will always have to be server code to do it. Whether that code is in a web server, a framework, a database, it doesn't matter. Someone has to write it. However, I could see some of the code, such as the code that actually builds the page the users sees, being pushed into the browser. But then, don't we already have that with XML and XSLT (or whatever?)
- voidfiles 17y ago
  couchDB folks are trying to create auth in client, they haven't succeeded yet, the crypto algorithms are a bit taxing on the browser, but they are trying.

chime 17y ago

Honest question: How would one go about implementing authentication/security into such a setup? Maybe it could work for 1-writer, many reader apps (blogs) but how do you handle user signups, accounts, and security with this?

thisduck 17y ago
I think CouchDB might have built-in authentication coming soon, but I'm not sure about that. There's always the option of using HTTP authentication.
- akeefer 17y ago
  Is that really good enough, though? For example, suppose that I write a blogging platform, and I want to ensure that a user can only query their own blog entries. How would I do that if the query is coming from the client (which always has to be untrusted) directly to the database? What prevents someone from rewriting the js client side so that it queries blog posts from other users? Or to prevent it from just sucking back all the blog posts in the DB and essentially DOSing the whole server? Doing per-user security directly in the DB with simple CRUD permissions per table would be enough of a headache, but most applications eventually require finer-grained security than that, and for performance reasons you also don't want a client to be able to execute just any arbitrary query. It seems like this is pretty close to same trap a lot of people fall into of only enforcing data validation client-side, or only enforcing things like view permissions client-side (by not rendering links), which leaves all sorts of holes open.
  - Periodic 17y ago
    I kept hoping the next paragraph would address this, but it didn't. It's cool and all, but it sounds like you're still going to basically need a server stack there to enforce permissions and some logic and consistency things. For example, say users have some private data. What stops me from modifying the javascript to insert a record that points to someone else's email address in my record? Unless the database can see this and prevent it I might then be looking at or even able to change someone else's email on their account. It can get very hairy if you don't have full control over the database interaction because you have to start guarding against arbitrary database operations.

moe 17y ago

Yes, history keeps repeating. It's hilarious to watch these kids reinvent, well, everything, over and over. So, here we have the return of the fat client, episode 20. And as with all the other episodes the standard question remains: If you're going fat-client then why on earth stick to a platform as horrible as HTML/JS?

rcoder 17y ago
The reasons to stick with DHTML/JS as a "thick client" development platform are simple: decent, free development tools, the ability to interpose proxies and application middleware between the client and server transparently, and a very, very large install base for the client runtime. That being said, I share much of your amusement at/disdain for the attitude of "OMG, look at this brand new thing I have made that is completely different from all those old things!"
- moe 17y ago
  I'm not sure about these reasons. decent, free development tools Well, you can have these for any mature platform. Be it QT, Flex or even Java. I'm not sure what's more decent about the HTML toolchain. The often cited FireBug is, to me, merely an emergency bandaid that makes development at least possible but still far from enjoyable. the ability to interpose proxies and application middleware between the client and server transparently There's nothing stopping any fat-client to speak HTTP. You don't need to a browser for that. and a very, very large install base for the client runtime. I'd say installation base is a red herring when talking about cross-platform apps but I'll give you that "instant-on" is an argument. For that I'd point to Air, which can run hybrid in and outside the browser. I'm not arguing that HTML doesn't have it's place, mind you. But the extent to which it is abused nowadays is absurd.
  - shabda 17y ago
    > and a very, very large install base for the client runtime. You are underetimating this. For evrything else, (air, java, Qt, C#) I have to start a new app. My firefox is always on.

n8agrin 17y ago

With the power of CouchApp and _attachments, the javascript and HTML files needed to serve the application are served directly out of the database. That statement kind of troubles me. It shows that you're really just offloading all of the work from a normal app server to the data storage layer. From a "Mom look what I can do!" perspective this is cool, but, again, you're not eliminating your app server. Couchdb allows this because it uses HTTP as it's communication protocol, but one could do the same with MySQL, via an HTTP communication frontend, which sounds a lot like what Rails, Django, etc effectively are with some optimizations to make other non-data-storage operations faster.

richcollins 17y ago

When all you have is a hammer ... jQuery is not a good architecture for a full client application. jQuery is meant for flipping some dom attributes here and there. It does a poor job of modeling the UI state. Sinatra is also a poor architecture choice for the client since the client has persistent state. We already have a well designed client architecture. It's called Cocoa and its implemented in the browser as Cappuccino.

jherdman 17y ago
Interesting point. I tend to agree with you. I find myself hesitant about putting my business logic essentially on the front-end. With the current model we can hide some of the "secret sauce" that makes our applications unique on the server end. With something like Cappuccino (or Sammy.js, etc), how do we keep our secret sauce secret?
- shykes 17y ago
  > I find myself hesitant about putting > my business logic essentially on the front-end Leave the business logic on the server where it belongs - but hide it behind a REST API, and leave the rendering to the browser. I think that's the core argument, if you omit the "CouchDB as an app server" part (which is orthogonal).
  - ams6110 17y ago
    This was exactly the approach I took with an app about 4 - 5 years ago. Back then XML not JSON was the data transport format, but I kept it lightweight. The UI was built in the browser using XSLT to generate HTML. Additional transforms tied to UI events allowed filtering, sorting, etc. all on the client. IE, for all its other flaws, actually supported this much better than any other browser at that time and we were developing in an IE-only environment. Business logic was on the server in stored procedures, which were exposed in a simple web service api so they could be called directly by the browser script logic. This also made it very testable because the stored procedures could be invoked by testing scripts that did not depend on the presence of any middle tier or UI at all. It also would have been a simple matter to build other client front-ends, as long a platform could work with XML and HTTP it could in theory be a client. The XSLT to render the UI from XML could get a bit verbose but despite that it turned out to be a very productive way to work. The downsides at the time were that IE was slow to render when you injected the HTML output of the transforms into the body.innerHTML property; this became noticeable if the generated page was large, but on the plus side this was a constraint against developing overly-complex pages.

dolinsky 17y ago

This might work for the simplest of sites like some have pointed out (e.g. a blog) but what I can't accept is having application logic on the frontend. Beyond authentication (let's say OAuth et all solve that issue down the road), one of the benefits of having serverside code is that when it comes down to it, you as a developer don't care if the user messes with the frontend (exposed) business logic (usually form validation of some type) because you're always checking it again / cleansing it on the serverside. That's the tip of the iceberg...ranking algorithms, limits on certain activities (rules in general). Now, that serverside code can be javascript serverd on something akin to 10gen if javascript is their tool of choice, but exposing any of those to the user so that they may edit them without any secondary sanity check is unacceptable.

sunkencity 17y ago

learning JavaScript & prototype i wrote a Twitter clone around this idea. I put up a number of textfiles in different user directories, and turned apaches directory listings on, and voilà a very basic restful interface. I also added post somehow, maybe a php script. The client-side script could read who to follow from the server and by itself performed the task of assembling the timeline which was the CPU and IO extensive task that twitter had problems scaling with. Not sure the extra bandwidth cost of performing this client side would be worth it, but there's almost no logic at all server side so there's not much scaling of processor power at least. Programming with prototype was fun, but then I found jQuery...

cmelbye 17y ago

Is anyone actually using this architecture?

californiaguy2 17y ago

Stop the madness. Just stop it.

tzury 17y ago

How on earth are these guys going to prevent a user from reading all the credit cards from that couch-db via its json interface?