Blockchain API to determine transaction confirmations

Question

I am trying to identify whether a transaction in the bitcoin blockchain has been confirmed or not. I have accessed a JSON representation of the transaction from blockchain.info using this url: https://blockchain.info/tx/62f9419e56ac1b628840aaf52307867f9856d7a52b3c1d945a9938a3021cbf2c?show_adv=false&format=json

I can not find anything in the response that indicates how many confirmations it has...

{"block_height":221580,"time":1361068368,"inputs":[{"prev_out":{"n":0,"value":100000000,"addr":"1NaPjDPGcfaVCBd3cTmy4zEPjRbDwzkW49","tx_index":53213157,"type":0}},{"prev_out":{"n":0,"value":100000,"addr":"1FDBdn8cseukiteu1myGQCfgYnncdMNpFk","tx_index":53252395,"type":0}},{"prev_out":{"n":0,"value":100000000,"addr":"13QRi4W5bq3FWrNGrWGcF1dH4mSWD6Huun","tx_index":52575903,"type":0}},{"prev_out":{"n":0,"value":100000000,"addr":"1MhEJx1BodWATGxoZ7az3GnmUQwx2adCG2","tx_index":53376409,"type":0}},{"prev_out":{"n":1,"value":90000000,"addr":"1FosGa87ZSjoagVu1j8djiJKzUeLkhhp6P","tx_index":53308634,"type":0}},{"prev_out":{"n":0,"value":200000,"addr":"1DZzEunCP1SxBsz2aZah2q9WAFuYSsDrq9","tx_index":53272656,"type":0}},{"prev_out":{"n":1,"value":98500000,"addr":"19q8NEgZKQcQMMx5z16JETbe1bx6StNZfj","tx_index":53506579,"type":0}},{"prev_out":{"n":0,"value":100000000,"addr":"15LXjh36usUspAYsGnhURVEnPn86W7SPSu","tx_index":53532799,"type":0}},{"prev_out":{"n":1,"value":119000000,"addr":"1PNbeqfPgMjjL6sLdXqkNZyCSkGFHop3bz","tx_index":53492488,"type":0}},{"prev_out":{"n":1,"value":150000000,"addr":"153hqmnNqUM8RGWdLE12tj74aAyS9U2pe7","tx_index":53283295,"type":0}},{"prev_out":{"n":0,"value":100000000,"addr":"149BGgDjaMyYfYnrja4asYtuUnpsBjobnH","tx_index":53440208,"type":0}},{"prev_out":{"n":167,"value":35000,"addr":"1F3eAsYGC45s2Q8XiE7ywGXMr8QLB8FTCD","tx_index":53578752,"type":0}},{"prev_out":{"n":862,"value":5000,"addr":"1CD4Dcy3yUiBejmQX1hKfJi1y5ysAX9RwZ","tx_index":53578752,"type":0}},{"prev_out":{"n":0,"value":60000000,"addr":"1Q7hDXko9U8MxoAZGmYk2se6tf8WFSQbUK","tx_index":53305081,"type":0}},{"prev_out":{"n":1,"value":98000000,"addr":"1RuMjWETvUPAUqfJKhZ4GBo5tKuszbDTA","tx_index":53521527,"type":0}},{"prev_out":{"n":0,"value":100000000,"addr":"17rBkeKtc7APY5PQjbicBbucfaUA1PZSpm","tx_index":53511134,"type":0}},{"prev_out":{"n":0,"value":169216027,"addr":"1EBz5v7dJfBPJzSwivVQcY19eT5hUBxa8w","tx_index":53194652,"type":0}},{"prev_out":{"n":1,"value":80000000,"addr":"1KLn85reRxN1JZL1S3gD2Kp2x8LZ14rz6S","tx_index":53194567,"type":0}},{"prev_out":{"n":0,"value":100000000,"addr":"1EppQ2h8Ddvp1vsoSb2DLJqJAws2DrYnv9","tx_index":53190665,"type":0}},{"prev_out":{"n":174,"value":2,"addr":"1CDDR1vZtZPWc48v4brHmka3tDpXbuT9wd","tx_index":53620404,"type":0}},{"prev_out":{"n":1,"value":100000000,"addr":"12zQxFPPh5rsUyakdZZyADj2N5bFRFZRcd","tx_index":53540021,"type":0}},{"prev_out":{"n":1,"value":801624197,"addr":"1JEjtpHB7aZJm3QSRp76qQqchFfs4TjDeE","tx_index":53526428,"type":0}},{"prev_out":{"n":1,"value":100000000,"addr":"1K1Sn9V775d7i94voiYLLUSaFNUQ9BVj9Q","tx_index":53430153,"type":0}},{"prev_out":{"n":1156,"value":1,"addr":"1CxXkpmJ9Nr4S9b3rKeKU5WWLXGp5nv553","tx_index":53619724,"type":0}},{"prev_out":{"n":0,"value":99950000,"addr":"1Hp5GdoX4oXmjUD6ZRKvXNJQCZp2sk712c","tx_index":53229930,"type":0}},{"prev_out":{"n":1,"value":98000000,"addr":"12aqif4GXBd17N6EFj4onrHLd8febY4n6j","tx_index":53160076,"type":0}},{"prev_out":{"n":0,"value":357452267,"addr":"146eveRJD2YnxvNBw4hHtZn8xR3LHHVxtH","tx_index":53651895,"type":0}},{"prev_out":{"n":1,"value":60000000,"addr":"1FZximueHPa9sqTZSg2Q4LAsg91dZaJK5D","tx_index":53640062,"type":0}},{"prev_out":{"n":1,"value":100000000,"addr":"12VL7U1BLf8kLrkN3sca9w5dGVhVAy1kvD","tx_index":53578503,"type":0}},{"prev_out":{"n":0,"value":67315003,"addr":"1BbYNxYAGJJJz6wP4pK5eHmwcieRSiPDZm","tx_index":53437082,"type":0}},{"prev_out":{"n":1,"value":100000000,"addr":"1DoTTLAs5VUm2QHBXeL34h2kSfYnqSpsCj","tx_index":53116751,"type":0}},{"prev_out":{"n":1,"value":195951000,"addr":"1Epje2MuDrckP4zVJmRXyEu5jWby2MvgHy","tx_index":53599874,"type":0}},{"prev_out":{"n":25,"value":1,"addr":"1CdACYi1JQDGekGPPc8bd3vq5d5v6s2KKY","tx_index":53620401,"type":0}},{"prev_out":{"n":105,"value":2,"addr":"15dsKW8yotixATZdDomBkRJh7YvzJJ4z7X","tx_index":53620401,"type":0}},{"prev_out":{"n":1,"value":90000000,"addr":"17ra7TQoPSmrxvLXGhupexd3Dk9fnZLM8Q","tx_index":53675760,"type":0}},{"prev_out":{"n":0,"value":100000000,"addr":"1Fm2j4k7XK8veWdeJaxDuZdujdQQh3mj9j","tx_index":53696368,"type":0}},{"prev_out":{"n":39,"value":1500,"addr":"1PB3DrsvvTMkxv7AoV5FdMAVbrnv1R9AvF","tx_index":53366964,"type":0}},{"prev_out":{"n":1,"value":70000000,"addr":"1HDxhL7H8thYC9RaLwACRoeTP6cjTERzkq","tx_index":53197639,"type":0}},{"prev_out":{"n":0,"value":60000000,"addr":"1Mzt5Y815fnf3rbCigx411bmUGqTiAMMMf","tx_index":53534495,"type":0}},{"prev_out":{"n":0,"value":3000000,"addr":"191cP1rSfJX9kATiujqbavKPHta8ryPbUk","tx_index":53397518,"type":0}},{"prev_out":{"n":0,"value":80000000,"addr":"1E7zhSRBexQYN98PxKZrnocZzb7yuCoobF","tx_index":53616202,"type":0}},{"prev_out":{"n":0,"value":60000000,"addr":"1DNGJSkn2jaBtzHpeu2EV8Za7GzLkYRKrk","tx_index":53211317,"type":0}},{"prev_out":{"n":0,"value":100000000,"addr":"1FPHkZfftpfBVYg46sBAZmU7k4R6nMWjgm","tx_index":53714935,"type":0}},{"prev_out":{"n":1,"value":80000000,"addr":"1NJmpCAfoeZa8M8RoWCT1PAs85k4URKwuL","tx_index":53437066,"type":0}},{"prev_out":{"n":1,"value":320000000,"addr":"17MCmBPgv2SEKsmGf1o7X6qbK59C1Pnwr3","tx_index":53584050,"type":0}},{"prev_out":{"n":0,"value":100000000,"addr":"1KrtH7ceJthEfBFd8t9G4Vohj2myGB1eDj","tx_index":53212472,"type":0}},{"prev_out":{"n":1,"value":103000000,"addr":"13zZzqKR3XYPUKpLWvGkimSJbDMaJim9Ru","tx_index":53218032,"type":0}},{"prev_out":{"n":1,"value":92500000,"addr":"1G5EdCerj7Yryoc4tpmCrFe7rvkbLcjHtz","tx_index":53633538,"type":0}},{"prev_out":{"n":0,"value":97800000,"addr":"1K59Q1UJSULsHhs4Rv8PiakEhDK689jQSj","tx_index":53232395,"type":0}}],"vout_sz":2,"relayed_by":"184.71.200.221","hash":"62f9419e56ac1b628840aaf52307867f9856d7a52b3c1d945a9938a3021cbf2c","vin_sz":52,"tx_index":53744354,"ver":1,"out":[{"n":0,"value":1000000,"addr":"1cm8zPZqjfWs5MBg8yKxJwWvDAkqF4CVu","tx_index":53744354,"type":0},{"n":1,"value":5000000000,"addr":"1EGP5pSnttKRdAcPxdiTviSrjsyHEAnXhy","tx_index":53744354,"type":0}],"size":9439}

Answer 1

The concept of "confirmation" on Bitcoin essentially translates to how many blocks have been generated since the block containing transaction. In other words, you'll have to issue another request to get the current network block count (http://blockchain.info/q/getblockcount), and the confirmation count then becomes current_block_count - transaction_block_height + 1. Note that block_height is only present in the response if at least one block was generated since (i.e. new transactions may not even include the element).