CODEWITHSUNDEEP
iosobjective-ccsvnsstringnsurlrequest
AlexR
AlexR

Reputation: 5644

Efficiently parsing a CSV file from a web service (using CHSVParser)

My app is currently parsing CSV files from a web service by using a combination of componentsSeparatedByCharactersInSet and componentsSeparatedByString methods. As the files are quite large (> 1 mb on average), parsing takes a couple of seconds on an iPad, which is too slow. The memory footprint of my solution is an issue too (I am holding the full text file in memory). This is why I am looking for a faster and more memory-efficient solution. I came across CHCSVParser which can parse NSInputStreams directly, e.g. 

NSInputStream *stream = [NSInputStream inputStreamWithFileAtPath:file]; 
CHCSVParser * p = [[CHCSVParser alloc] initWithInputStream:stream 
    usedEncoding:&encoding delimiter:';'];

(Source from the sample project on CHCSVParser)

My question:

How can I get an NSInputStream as the result of an NSURLRequest? (Currently I am getting the whole CSV file as a NSData object and converting it to NSString in order to parse it).

Could I use the NSInputStream from an NSURLRequest directly with CHSVParser?

Would you generally recommend using CHCSVParsers initWithInputStream method with a NSURLRequest or rather download the document to memory and parse if after the full download?

Upvotes: 0

Views: 424

Answers (1)

Idles
Idles

Reputation: 1131

Download the file to disk using NSURLConnectionDelegate and NSOutputStream (that way you use as little memory as possible while downloading) and then open an NSInputStream to the same file and pass it into CHCSVParser.

Upvotes: 2

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