get pending transactions in `txpool` via web3

Question

I want to monitor the mempool for my pending transactions. I understand one can monitor pending transactions by eth_subscribe (e.g. answered here). But some of my transactions have been stuck in the txpool, and they don't seem to show up in the result ofeth_subscribe`.

I'm confused by the difference between mempool, txpool, and pending transactions returned from eth_subscribe.

1. how to retrieve transactions that are already in txpool?
2. eth_subscribe only returns txid. Some of them can't be found by eth.getTransaction. What does that mean?
3. Transactions returned from eth_subscribe are different from what are in txpool. It's unclear whether they form a superset of txpool or not.

Answer 1

Actually Web3 does have a method to return what you looking for you can find the details here: https://web3py.readthedocs.io/en/fix_docs_build/web3.txpool.html#web3.txpool.TxPool.content

A simple call would be as follows:

w3 = Web3(HTTPProvider("http://provider.com"))
w3.geth.txpool.content()

This gets you nicely all the data of the pending transactions in a dict that looks like this:

{
'pending': {
    '0x0216d5032f356960cd3749c31ab34eeff21b3395': {
    806: [{
        'blockHash': "0x0000000000000000000000000000000000000000000000000000000000000000",
        'blockNumber': None,
        'from': "0x0216d5032f356960cd3749c31ab34eeff21b3395",
        'gas': "0x5208",
        'gasPrice': "0xba43b7400",
        'hash': "0xaf953a2d01f55cfe080c0c94150a60105e8ac3d51153058a1f03dd239dd08586",
        'input': "0x",
        'nonce': "0x326",
        'to': "0x7f69a91a3cf4be60020fb58b893b7cbb65376db8",
        'transactionIndex': None,
        'value': "0x19a99f0cf456000"
    }]
    },
    '0x24d407e5a0b506e1cb2fae163100b5de01f5193c': {
    34: [{
        'blockHash': "0x0000000000000000000000000000000000000000000000000000000000000000",
        'blockNumber': None,
        'from': "0x24d407e5a0b506e1cb2fae163100b5de01f5193c",
        'gas': "0x44c72",
        'gasPrice': "0x4a817c800",
        'hash': "0xb5b8b853af32226755a65ba0602f7ed0e8be2211516153b75e9ed640a7d359fe",
        'input': "0xb61d27f600000000000000000000000024d407e5a0b506e1cb2fae163100b5de01f5193c00000000000000000000000000000000000000000000000053444835ec580000000000000000000000000000000000000000000000000000000000000000006000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
        'nonce': "0x22",
        'to': "0x7320785200f74861b69c49e4ab32399a71b34f1a",
        'transactionIndex': None,
        'value': "0x0"
    }]
    }
},
'queued': {
    '0x976a3fc5d6f7d259ebfb4cc2ae75115475e9867c': {
    3: [{
        'blockHash': "0x0000000000000000000000000000000000000000000000000000000000000000",
        'blockNumber': None,
        'from': "0x976a3fc5d6f7d259ebfb4cc2ae75115475e9867c",
        'gas': "0x15f90",
        'gasPrice': "0x4a817c800",
        'hash': "0x57b30c59fc39a50e1cba90e3099286dfa5aaf60294a629240b5bbec6e2e66576",
        'input': "0x",
        'nonce': "0x3",
        'to': "0x346fb27de7e7370008f5da379f74dd49f5f2f80f",
        'transactionIndex': None,
        'value': "0x1f161421c8e0000"
    }]
    },
    '0x9b11bf0459b0c4b2f87f8cebca4cfc26f294b63a': {
    2: [{
        'blockHash': "0x0000000000000000000000000000000000000000000000000000000000000000",
        'blockNumber': None,
        'from': "0x9b11bf0459b0c4b2f87f8cebca4cfc26f294b63a",
        'gas': "0x15f90",
        'gasPrice': "0xba43b7400",
        'hash': "0x3a3c0698552eec2455ed3190eac3996feccc806970a4a056106deaf6ceb1e5e3",
        'input': "0x",
        'nonce': "0x2",
        'to': "0x24a461f25ee6a318bdef7f33de634a67bb67ac9d",
        'transactionIndex': None,
        'value': "0xebec21ee1da40000"
    }],
    6: [{
        'blockHash': "0x0000000000000000000000000000000000000000000000000000000000000000",
        'blockNumber': None,
        'from': "0x9b11bf0459b0c4b2f87f8cebca4cfc26f294b63a",
        'gas': "0x15f90",
        'gasPrice': "0x4a817c800",
        'hash': "0xbbcd1e45eae3b859203a04be7d6e1d7b03b222ec1d66dfcc8011dd39794b147e",
        'input': "0x",
        'nonce': "0x6",
        'to': "0x6368f3f8c2b42435d6c136757382e4a59436a681",
        'transactionIndex': None,
        'value': "0xf9a951af55470000"
    }, {
        'blockHash': "0x0000000000000000000000000000000000000000000000000000000000000000",
        'blockNumber': None,
        'from': "0x9b11bf0459b0c4b2f87f8cebca4cfc26f294b63a",
        'gas': "0x15f90",
        'gasPrice': "0x4a817c800",
        'hash': "0x60803251d43f072904dc3a2d6a084701cd35b4985790baaf8a8f76696041b272",
        'input': "0x",
        'nonce': "0x6",
        'to': "0x8db7b4e0ecb095fbd01dffa62010801296a9ac78",
        'transactionIndex': None,
        'value': "0xebe866f5f0a06000"
    }],
    }
}
}

I provided the example in Python, since you didnt specify any language you working on.

Answer 2

If you are getting confused, I suggest you use JSON-RPC

curl -X POST -d '{"jsonrpc":"2.0","method":"txpool_status","params":[],"id":1}' http://ip:port
curl -X POST -d '{"jsonrpc":"2.0","method":"txpool_content","params":[],"id":1}' http://ip:port
curl -X POST -d '{"jsonrpc":"2.0","method":"txpool_inspect","params":[],"id":1}' http://ip:port

If you are familiar with creating POST requests in the language you are using, change the above curl commands to them and use.