I have Xamarin iOS app with in-app products. I get base64 encoded app receipt:
NSUrl receiptURL = NSBundle.MainBundle.AppStoreReceiptUrl;
String receiptData = receipt.GetBase64EncodedString(0);
According to Apple docs 7.0+ app receipt is packed in PKCS7 container using ASN1. When I send it to apple server it returns receipt in JSON. But I want to parse it locally to know what iaps user does already have. I don't need validation, as Apple does it remotely, I just need to get receipts for purchased inaps.
So far, as an investigation, I've parsed it in php with phpseclib, manually (no idea how to do this programatically) located receipt and parsed it as well.
$asn_parser = new File_ASN1();
//parse the receipt binary string
$pkcs7 = $asn_parser->decodeBER(base64_decode($f));
//print_r($pkcs7);
$payload_sequence = $pkcs7[0]['content'][1]['content'][0]['content'][2]['content'];
$pld = $asn_parser->decodeBER($payload_sequence[1]['content'][0]['content']);
//print_r($pld);
$prd = $asn_parser->decodeBER($pld[0]['content'][21]['content'][2]['content']);
print_r($prd);
But even this way I've got a mess of attributes, each looks like:
Array
(
[start] => 271
[headerlength] => 2
[type] => 4
[content] => 2016-08-22T13:22:00Z
[length] => 24
)
It is not human readable, I need something like (output with print_r of returned by Apple) :
[receipt] => Array
(
[receipt_type] => ProductionSandbox
[adam_id] => 0
[app_item_id] => 0
[bundle_id] => com.my.test.app.iOS
...
[in_app] => Array
(
[0] => Array
(
[quantity] => 1
[product_id] => test_iap_1
[transaction_id] => 1000000230806171
...
[is_trial_period] => false
)
)
)
Things seem too complicated, I hardly believe unpacking receipt is so complex. Does anybody know how to manage this? I've found this post but library is written in objective-C which is not applicable to my current environment. I'd say sources of this lib are frightened me: so much complex code just to unpack standartized container. I mean working with json, bson, etc. is very easy, but not asn1.
