November 2014 - Pharo-users

Pharo and ODBC

by olivier auverlot

Hi, I try to use the ODBC framework presents in the configurations list and named "ODBC (TorstenBergmann.5)" I want connect Pharo to a Postgresql server and I installed the latest version of the ODBC driver. The datasource is configured as system datasource. The connection test is ok. My computer uses Windows 7 64 bits. In Pharo, I try to connect with the following code: connection := ODBCConnection dsn: 'mysource' user: 'myuser' password: 'mypassword'. connection close. The connection fails and I get an error message: "The data source (DSN) has a specified architecture incompatibility between the driver and the application". Someone have an idea about this problem ? Someone works with the ODBC solution ? Best regards Olivier

Nov. 20, 2014

Re: [Pharo-users] Messaging solutions for Pharo

by Sven Van Caekenberghe

> On 19 Nov 2014, at 20:52, Esteban A. Maringolo <emaringolo(a)gmail.com> wrote: > > My current use case is pretty simple, being able to push requests to the remote devices, and gather the data back, assuming the remote devices (clients) are already connected to the server, which is a client-related problem with any messaging solution. > > I learn about MQTT when looking for alternatives to Google Cloud Messaging for Android (which is built on to of XMPP). Facebook Messenger uses MQTT. > > I don't want to develop an overkill solution that could delay deliverance of value to my customer, though I find implementing an MQ/MQTT solution intellectually challenging. I even read the standard a few months ago, and it seems to be simpler than expected. I'd love to go down the "implement MQTT server in Pharo", I would lose a real MQ scalability, but it could be a good way to learn the protocol, and an alternative to Mosquitto [1] with the benefits of having a server inside the image. > > Do you have experience with the scalability of Zinc WebSockets? > How many of them can a single Pharo image handle? The I/O would be minimal (< 1KB) per message, and the requests would be measured in minutes instead of seconds. Although a 50 ws frames/sec peak during a couple of seconds is feasible. I don't have any production level experience with (Zinc) WebSockets. But we have some Pharo images in production doing related things. Based on that I would say 100s of concurrent open connections is doable, but I would be careful if you know you will scale to 1000s. Why ? Because each connection is a socket(stream) with 3 semaphores and a process/thread. It will still work, but it might be harder to keep things together. BTW, this is not a Pharo problem per se, it will be hard(er) everywhere. I just read that MQTT over WebSockets also exists ;-) I guess that you have no RabbitMQ experience so maybe that scares you a bit, you will have to learn some new things, but it is not hard (and it is quite interesting). In terms of doing MQTT directly in Pharo, I would start with the client side, it can't be very hard to do (there are many clients already). > Regards, > > [1] http://mosquitto.org/ > > El Wed Nov 19 2014 at 4:22:56 PM, Sven Van Caekenberghe <sven(a)stfx.eu> escribiÃ³: > Hey Esteban, > > Since you seem to need to scale to 1000s of concurrent connections, I would go for option 2. RabbitMQ will then work as a demultiplexer and you gain options for using more than one Pharo worker for processing traffic, if that ever becomes necessary. > > BTW, I never heard of MQTT and it seems pretty interesting, thanks ! I will read about it tonight. > > Sven > > > On 19 Nov 2014, at 19:06, Esteban A. Maringolo <emaringolo(a)gmail.com> wrote: > > > > Hi, > > > > I'll be needing to add bidirectional messaging to our current Android (Java) application, and as usual I'm expecting to manage the server side of the communication with Pharo. > > > > I'm evaluating two alternatives, but I'm in open to other, proven, options. > > > > Option 1. WebSockets > > Open a WebSocket on each device, and push/retrieve messages from each of these, tracking the device id if I need to recreate a new socket (avoiding recreating new sockets in case of connectivity issues, very common). > > > > Option 2. MQTT [1] > > This is basically a mobile oriented MQ, super low footprint on mobile. > > For what I saw, I could implement the server using an intermediate MQ (RabbitMQ) and use STOMP to connect to it. > > > > Option 3. XMPP [3] > > Provides several features I'll need in the future, like file transfer in addition to regular text messaging. It is very well supported in Android with Smack [4], but I don't know if we have a Pharo server for it, or if somebody ever played with it. > > > > By means of simplicity and use load I favor option 1, because I can understand it better, and as everything moves towards web based technologies, I could implement WAMP [5] on top of that in the future. > > > > Right now I'd need to have a hundred websockets opened at the same time, which doesn't sound like a heavy load to me, but I certainly don't know. In the future it could be an order of magnitude bigger, and that's why I don't discard more complex solutions like XMPP or MQTT. > > > > Regards! > > > > > > [1] http://mqtt.org/ > > [2] https://github.com/svenvc/docs/blob/master/neo/stamp.md > > [3] http://xmpp.org/ > > [4] http://www.igniterealtime.org/projects/smack/ > > [5] http://wamp.ws/ > > > > > >

Nov. 19, 2014

Re: [Pharo-users] Messaging solutions for Pharo

by Esteban A. Maringolo

My current use case is pretty simple, being able to push requests to the remote devices, and gather the data back, assuming the remote devices (clients) are already connected to the server, which is a client-related problem with any messaging solution. I learn about MQTT when looking for alternatives to Google Cloud Messaging for Android (which is built on to of XMPP). Facebook Messenger uses MQTT. I don't want to develop an overkill solution that could delay deliverance of value to my customer, though I find implementing an MQ/MQTT solution intellectually challenging. I even read the standard a few months ago, and it seems to be simpler than expected. I'd love to go down the "implement MQTT server in Pharo", I would lose a real MQ scalability, but it could be a good way to learn the protocol, and an alternative to Mosquitto [1] with the benefits of having a server inside the image. Do you have experience with the scalability of Zinc WebSockets? How many of them can a single Pharo image handle? The I/O would be minimal (< 1KB) per message, and the requests would be measured in minutes instead of seconds. Although a 50 ws frames/sec peak during a couple of seconds is feasible. Regards, [1] http://mosquitto.org/ El Wed Nov 19 2014 at 4:22:56 PM, Sven Van Caekenberghe <sven(a)stfx.eu> escribiÃ³: > Hey Esteban, > > Since you seem to need to scale to 1000s of concurrent connections, I > would go for option 2. RabbitMQ will then work as a demultiplexer and you > gain options for using more than one Pharo worker for processing traffic, > if that ever becomes necessary. > > BTW, I never heard of MQTT and it seems pretty interesting, thanks ! I > will read about it tonight. > > Sven > > > On 19 Nov 2014, at 19:06, Esteban A. Maringolo <emaringolo(a)gmail.com> > wrote: > > > > Hi, > > > > I'll be needing to add bidirectional messaging to our current Android > (Java) application, and as usual I'm expecting to manage the server side of > the communication with Pharo. > > > > I'm evaluating two alternatives, but I'm in open to other, proven, > options. > > > > Option 1. WebSockets > > Open a WebSocket on each device, and push/retrieve messages from each of > these, tracking the device id if I need to recreate a new socket (avoiding > recreating new sockets in case of connectivity issues, very common). > > > > Option 2. MQTT [1] > > This is basically a mobile oriented MQ, super low footprint on mobile. > > For what I saw, I could implement the server using an intermediate MQ > (RabbitMQ) and use STOMP to connect to it. > > > > Option 3. XMPP [3] > > Provides several features I'll need in the future, like file transfer in > addition to regular text messaging. It is very well supported in Android > with Smack [4], but I don't know if we have a Pharo server for it, or if > somebody ever played with it. > > > > By means of simplicity and use load I favor option 1, because I can > understand it better, and as everything moves towards web based > technologies, I could implement WAMP [5] on top of that in the future. > > > > Right now I'd need to have a hundred websockets opened at the same time, > which doesn't sound like a heavy load to me, but I certainly don't know. In > the future it could be an order of magnitude bigger, and that's why I don't > discard more complex solutions like XMPP or MQTT. > > > > Regards! > > > > > > [1] http://mqtt.org/ > > [2] https://github.com/svenvc/docs/blob/master/neo/stamp.md > > [3] http://xmpp.org/ > > [4] http://www.igniterealtime.org/projects/smack/ > > [5] http://wamp.ws/ > > > > > > >

Nov. 19, 2014

Re: [Pharo-users] Messaging solutions for Pharo

by Sven Van Caekenberghe

Hey Esteban, Since you seem to need to scale to 1000s of concurrent connections, I would go for option 2. RabbitMQ will then work as a demultiplexer and you gain options for using more than one Pharo worker for processing traffic, if that ever becomes necessary. BTW, I never heard of MQTT and it seems pretty interesting, thanks ! I will read about it tonight. Sven > On 19 Nov 2014, at 19:06, Esteban A. Maringolo <emaringolo(a)gmail.com> wrote: > > Hi, > > I'll be needing to add bidirectional messaging to our current Android (Java) application, and as usual I'm expecting to manage the server side of the communication with Pharo. > > I'm evaluating two alternatives, but I'm in open to other, proven, options. > > Option 1. WebSockets > Open a WebSocket on each device, and push/retrieve messages from each of these, tracking the device id if I need to recreate a new socket (avoiding recreating new sockets in case of connectivity issues, very common). > > Option 2. MQTT [1] > This is basically a mobile oriented MQ, super low footprint on mobile. > For what I saw, I could implement the server using an intermediate MQ (RabbitMQ) and use STOMP to connect to it. > > Option 3. XMPP [3] > Provides several features I'll need in the future, like file transfer in addition to regular text messaging. It is very well supported in Android with Smack [4], but I don't know if we have a Pharo server for it, or if somebody ever played with it. > > By means of simplicity and use load I favor option 1, because I can understand it better, and as everything moves towards web based technologies, I could implement WAMP [5] on top of that in the future. > > Right now I'd need to have a hundred websockets opened at the same time, which doesn't sound like a heavy load to me, but I certainly don't know. In the future it could be an order of magnitude bigger, and that's why I don't discard more complex solutions like XMPP or MQTT. > > Regards! > > > [1] http://mqtt.org/ > [2] https://github.com/svenvc/docs/blob/master/neo/stamp.md > [3] http://xmpp.org/ > [4] http://www.igniterealtime.org/projects/smack/ > [5] http://wamp.ws/ > >

Nov. 19, 2014

Re: [Pharo-users] Messaging solutions for Pharo

by Andres Fortier

Hi Esteban, Never used either of them, but IIRC there was a Jabber package in Visualworks (JabberXMPP?), although not sure if it provided both client and server. There is also http://www.squeaksource.com/@zQrCJXpxIQLxqde8/tV369AO0. Seems dated, but maybe worth a shot considering you only need the server side? HTH, AndrÃ©s On Wed, Nov 19, 2014 at 3:06 PM, Esteban A. Maringolo <emaringolo(a)gmail.com> wrote: > Hi, > > I'll be needing to add bidirectional messaging to our current Android > (Java) application, and as usual I'm expecting to manage the server side of > the communication with Pharo. > > I'm evaluating two alternatives, but I'm in open to other, proven, options. > > Option 1. WebSockets > Open a WebSocket on each device, and push/retrieve messages from each of > these, tracking the device id if I need to recreate a new socket (avoiding > recreating new sockets in case of connectivity issues, very common). > > Option 2. MQTT [1] > This is basically a mobile oriented MQ, super low footprint on mobile. > For what I saw, I could implement the server using an intermediate MQ > (RabbitMQ) and use STOMP to connect to it. > > Option 3. XMPP [3] > Provides several features I'll need in the future, like file transfer in > addition to regular text messaging. It is very well supported in Android > with Smack [4], but I don't know if we have a Pharo server for it, or if > somebody ever played with it. > > By means of simplicity and use load I favor option 1, because I can > understand it better, and as everything moves towards web based > technologies, I could implement WAMP [5] on top of that in the future. > > Right now I'd need to have a hundred websockets opened at the same time, > which doesn't sound like a heavy load to me, but I certainly don't know. In > the future it could be an order of magnitude bigger, and that's why I don't > discard more complex solutions like XMPP or MQTT. > > Regards! > > > [1] http://mqtt.org/ > [2] https://github.com/svenvc/docs/blob/master/neo/stamp.md > [3] http://xmpp.org/ > [4] http://www.igniterealtime.org/projects/smack/ > [5] http://wamp.ws/ > > >

Nov. 19, 2014

Messaging solutions for Pharo

by Esteban A. Maringolo

Hi, I'll be needing to add bidirectional messaging to our current Android (Java) application, and as usual I'm expecting to manage the server side of the communication with Pharo. I'm evaluating two alternatives, but I'm in open to other, proven, options. Option 1. WebSockets Open a WebSocket on each device, and push/retrieve messages from each of these, tracking the device id if I need to recreate a new socket (avoiding recreating new sockets in case of connectivity issues, very common). Option 2. MQTT [1] This is basically a mobile oriented MQ, super low footprint on mobile. For what I saw, I could implement the server using an intermediate MQ (RabbitMQ) and use STOMP to connect to it. Option 3. XMPP [3] Provides several features I'll need in the future, like file transfer in addition to regular text messaging. It is very well supported in Android with Smack [4], but I don't know if we have a Pharo server for it, or if somebody ever played with it. By means of simplicity and use load I favor option 1, because I can understand it better, and as everything moves towards web based technologies, I could implement WAMP [5] on top of that in the future. Right now I'd need to have a hundred websockets opened at the same time, which doesn't sound like a heavy load to me, but I certainly don't know. In the future it could be an order of magnitude bigger, and that's why I don't discard more complex solutions like XMPP or MQTT. Regards! [1] http://mqtt.org/ [2] https://github.com/svenvc/docs/blob/master/neo/stamp.md [3] http://xmpp.org/ [4] http://www.igniterealtime.org/projects/smack/ [5] http://wamp.ws/

Nov. 19, 2014

How to decide if a name can be used as a name for a new class?

by Stephan Eggermont

I found isLegalClassName, but that has interesting properties 'Object' isLegalClassName false 'Bla' isLegalClassName false 'One sentence' isLegalClassName false. Stephan

Nov. 19, 2014

Re: [Pharo-users] PharoS VM

by Rafael Luque

Thank you! A brief explanation in the zeroconf page would be interesting for newbies like me, because I don't remember any mention to these types of VMs in the Pharo books available. Rafa 2014-11-19 13:26 GMT+01:00 Esteban Lorenzano <estebanlm(a)gmail.com>: > > On 19 Nov 2014, at 13:24, Rafael Luque <rafael.luque.leiva(a)gmail.com> > wrote: > > Another noob question. > > What's the difference between these two options I see in get.pharo.org? > > get.pharo.org/vmLatest This script downloads the latest Pharo VM. > > > latest Cog (JIT) > > get.pharo.org/vmSLatest This script downloads the latest PharoS VM. > > > latest Stack (No JIT) > > > cheers, > Esteban > > > Thank you. > > Rafael Luque > > > > > > >

Nov. 19, 2014

Re: [Pharo-users] PharoS VM

by Mariano Martinez Peck

I think the PharoS is the Cog STACK VM, meaning there is no JIT. On Wed, Nov 19, 2014 at 9:24 AM, Rafael Luque <rafael.luque.leiva(a)gmail.com> wrote: > Another noob question. > > What's the difference between these two options I see in get.pharo.org? > > get.pharo.org/vmLatest This script downloads the latest Pharo VM. > get.pharo.org/vmSLatest This script downloads the latest PharoS VM. > > Thank you. > > Rafael Luque > > > > > > -- Mariano http://marianopeck.wordpress.com

Nov. 19, 2014

Re: [Pharo-users] PharoS VM

by Esteban Lorenzano

> On 19 Nov 2014, at 13:24, Rafael Luque <rafael.luque.leiva(a)gmail.com> wrote: > > Another noob question. > > What's the difference between these two options I see in get.pharo.org <http://get.pharo.org/>? > > get.pharo.org/vmLatest <http://get.pharo.org/vmLatest> This script downloads the latest Pharo VM. latest Cog (JIT) > get.pharo.org/vmSLatest <http://get.pharo.org/vmSLatest> This script downloads the latest PharoS VM. latest Stack (No JIT) cheers, Esteban > > Thank you. > > Rafael Luque > > > > >

Nov. 19, 2014