Python: Retrieve Offer_id from a manage offer operation?

Question

I am using the python py-stellar-base to create a new offer operation.

To manage the offer in the future I want to be able to retrieve the created offer_id from the completed transaction.

builder.append_manage_offer_op(
    selling_code=selling_asset_code,
    selling_issuer=selling_issuer,
    buying_code=buying_asset_code,
    buying_issuer=buying_issuer,
    amount=amount,
    price=price,
    offer_id=0,
    source=seller_address
)
builder.add_text_memo('Offer')
builder.sign()

builder.submit()

I have gone through the documentation and can't see how I should retrieve the offer_id after doing the submit.

Does the builder return the ID after a successful transaction?

Answer 1

It's contained in the horizon response which can be decoded like this:

response = builder.submit()

result_bytes = base64.b64decode(response['result_xdr'])
tx_result = Xdr.StellarXDRUnpacker(result_bytes).unpack_TransactionResult()

offerId = tx_result.result.results[0].tr.manageOfferResult.success.offer.offer.offerID

print(offerId)