I would have the create method accept a callback since doing synchronous HTTP with node is tricky and discouraged. While you are asynchronously creating this object (which may indicate a different method name should be used) you are ultimately returning an object that exposes an API appropriate for the server version without then having to do a bunch of conditional code in each exposed method.
-- Daniel R. <[email protected]> [http://danielr.neophi.com/] On Sat, May 10, 2014 at 10:03 PM, Tony Barbieri <[email protected]> wrote: > Thanks for the reply Daniel. > > Would the create method accept a callback? Could I and should I perform > the initial http request to find the server version synchronously? > > Thanks again, > > Tony > > > On Sat, May 10, 2014 at 3:46 PM, Daniel Rinehart <[email protected]>wrote: > >> Have your module expose a create method that makes the initial request to >> get the version and have that return an object with all of the logic tied >> to the specific server version to the callback. That way you can avoid >> needing to check the version in all the subsequent calls. >> >> -- Daniel R. <[email protected]> [http://danielr.neophi.com/] >> Hello! >> >> I am pretty new to nodejs and I'm writing a client api module that will >> provide CRUD operations by calling json-rpc methods on an outside server. >> The server provides it's currently running version via a json-rpc request >> and based on that the client api may or may not have additional >> functionality. >> >> My question is more of a design question than anything else. I'm not >> sure the best way to get the server's version and cache it within an >> asynchronous environment. I am currently using the http module to make the >> requests and the q module to use promises. Below is some pseudo code to >> illustrate basically what I have. >> >> >> function Client(url, opts) { >>> var info = { >>> 'url': url, >>> 'server_version': null >>> }; >>> }; >>> >> >> >> Client.prototype.server_version = function (cb) { >>> if (!this.info.server_version){ >>> this.request("info").then(function(result) { >>> this.info.server_version = result.version; >>> }).nodeify(cb); >>> } else { >>> cb(this.info.server_version); >>> }; >>> }; >>> >> >> >> Client.prototype.read = function(params, cb) { >>> this.server_version(function(err, result) { >>> if (result > [3, 3, 0]) { >>> ... >>> }; >>> else { >>> ... >>> } >>> }); >>> return this.request(params).nodeify(cb); >>> }; >>> >> >> >> Client.prototype.request = function(method) { >>> defer = Q.defer(); >>> ... >>> return defer.promise; >>> }; >> >> >> >> I guess my question is this the "right" way to deal with figuring out the >> server version to make logical decisions at various points in the code? I >> see a few issues with the way I am currently doing it, if the >> server_version is requested multiple times before it's been cached there >> will be unnecessary additional calls made to the server. It would be nice >> to have a better way to attach callbacks to the original promise that's >> made when the first request is sent out. Also using always using a >> callback and nested functions to check the server version feels a bit >> inelegant. I'm not sure if this is the way it needs to be done. Is this a >> situation where I would want to use yield? If so do I need to run the >> unstable 11.* version of Node to take advantage of that? >> >> I apologize in advance if this question is vague. I am trying to >> understand how to do something asynchronous that I would normally do >> synchronously, ie: halting code flow the first time a call to check the >> server_version is made and being able to reference >> "this.info.server_version" afterwards versus always having to use a >> callback to do the check. >> >> Any and all advice is much appreciated. >> >> Best, >> >> Tony >> >> -- >> Job board: http://jobs.nodejs.org/ >> New group rules: >> https://gist.github.com/othiym23/9886289#file-moderation-policy-md >> Old group rules: >> https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines >> --- >> You received this message because you are subscribed to the Google Groups >> "nodejs" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/nodejs/CAJhmvsQZf1_us0MKV%2BuYPyejA2C-W%2BGBAyO%3DNYUczsHbDG8Fqw%40mail.gmail.com<https://groups.google.com/d/msgid/nodejs/CAJhmvsQZf1_us0MKV%2BuYPyejA2C-W%2BGBAyO%3DNYUczsHbDG8Fqw%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> >> -- >> Job board: http://jobs.nodejs.org/ >> New group rules: >> https://gist.github.com/othiym23/9886289#file-moderation-policy-md >> Old group rules: >> https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines >> --- >> You received this message because you are subscribed to the Google Groups >> "nodejs" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/nodejs/CAETDeSBUJnvVfC0ZPRy7bT6HFnc5o_forJ_WmuZfgZ%2BagnxfUQ%40mail.gmail.com<https://groups.google.com/d/msgid/nodejs/CAETDeSBUJnvVfC0ZPRy7bT6HFnc5o_forJ_WmuZfgZ%2BagnxfUQ%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > -tony > > -- > Job board: http://jobs.nodejs.org/ > New group rules: > https://gist.github.com/othiym23/9886289#file-moderation-policy-md > Old group rules: > https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines > --- > You received this message because you are subscribed to the Google Groups > "nodejs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/nodejs/CAJhmvsThAuvjemEUuub_BHBJ5xakr6mX1hHJ50VGVwD-cBmvYg%40mail.gmail.com<https://groups.google.com/d/msgid/nodejs/CAJhmvsThAuvjemEUuub_BHBJ5xakr6mX1hHJ50VGVwD-cBmvYg%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- Job board: http://jobs.nodejs.org/ New group rules: https://gist.github.com/othiym23/9886289#file-moderation-policy-md Old group rules: https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines --- You received this message because you are subscribed to the Google Groups "nodejs" group. 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