Parsing JSON in iOS the right way

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4 points·adam0101··5 comments

The author is using a library that parses an entire JSON document in one go. In order to use this library, the author points out that the application must collect the entire document from the network before parsing the document. It does not work if the application passes chunks of the document to the parser.

An alternative approach is to use an incremental parser like YAJL. The application can feed chunks of the JSON document to the parser as the chunks arrive over the network. A clever application can update the UI before the entire document is received by examining the partially constructed object tree.

Right but for people new to iOS dev is this really the best way? Instead of giving a caveat why not give a solution that will work in all situations?

There's no caveat for using YAJL. An application can feed data to YAJL from connection:didReceiveData: and know that the document is complete in connectionDidFinish:. This works if there are one or many calls to connection:didReceiveData:.

Anybody new to iOS needs to learn that connection:didReceiveData: is called as data is received. There's no way around that. There are two ways to deal with this. The first is to buffer the data as the author suggests. The other approach is to use an incremental parser.

Agreed and that's why I wrote the post to get that info out there instead of having people struggle.

Good post. I think the same holds true for the NSXMLParser delegate (and probably many others, I'm still new to iOS).

The "foundCharacters" method is sometimes called multiple times before reaching the end of an element so it's best to assume you're receiving only part of the data.

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