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authorMarcello Stanisci <marcello.stanisci@inria.fr>2016-03-22 19:28:15 +0100
committerMarcello Stanisci <marcello.stanisci@inria.fr>2016-03-22 19:28:15 +0100
commit37cdbc1e2b4be69ac7d268b2db220d1c0754973b (patch)
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fixing some crossreferences and describing the purchase
tiggered by visiting the fulfillment URL
Diffstat (limited to 'integration-merchant.rst')
-rw-r--r--integration-merchant.rst104
1 files changed, 41 insertions, 63 deletions
diff --git a/integration-merchant.rst b/integration-merchant.rst
index ecc3ab8..289b9ce 100644
--- a/integration-merchant.rst
+++ b/integration-merchant.rst
@@ -2,57 +2,10 @@
Interaction with merchant websites
==================================
--------------
-Purchase Flow
--------------
-The purchase flow consists of the following steps:
-
-1. UA visits merchant's checkout page
-2. The merchant's checkout page notifies the wallet
- of the contract (``taler-deliver-contract``).
-3. The user reviews the contract inside the wallet
-4. The wallet directs the UA to the payment execution page
-5. The execution page must send the event ``taler-execute-payment`` with
- the contract hash of the payment to be executed.
-6. The wallet executes the payment in the domain context of the
- execution page and emits the ``taler-payment-result`` event
- on the execution page.
-7. The execution page reacts to the payment result (which
- is either successful or unsuccessful) by showing
- an appropriate response to the user.
-
-----------------
-Event Reference
-----------------
-
-.. topic:: ``taler-deliver-contract``
-
- The event takes an :ref:`offer <offer>` as event detail.
-
-.. topic:: ``taler-execute-payment``
-
- The event takes `H_contract` of a :ref:`Contract <tsref-type-Contract>` as event detail.
-
-.. topic:: ``taler-payment-result``
-
- The event takes the following object as event detail:
-
- .. code-block:: tsref
-
- {
- // was the payment successful?
- success: boolean;
-
- // human-readable indication of what went wrong
- hint: string;
- }
-
-
-
-----------------
+++++++++++++++++
Payment protocol
-----------------
+++++++++++++++++
The events descripted below get triggered when the user confirms its
purchase on a checkout page, or when by visiting some merchant's resource
@@ -75,6 +28,10 @@ a physical good on his screen, the user will receive it by mail.
IIG triggers different flows according to the user visiting an offering or a fulfillment
URL. For clarity, below are listed the steps taken when the user visits an offering URL.
+---------------------
+IIG by `offering` URL
+---------------------
+
1. The merchant sends the following object embedded in a `taler-confirm-contract` event
.. code-block:: tsref
@@ -82,7 +39,7 @@ URL. For clarity, below are listed the steps taken when the user visits an offer
{
// Contract and cryptographic information
contract_wrapper: {
- contract: :ref:`Contract <tsref-type-Contract>`;
+ contract: Contract;
// base32 of the merchant's signature over this contract
merchant_sig: string;
// base32 of this contract's hashcode
@@ -95,20 +52,20 @@ URL. For clarity, below are listed the steps taken when the user visits an offer
}
2. The wallet's reaction is dual: it can either let the user pay for this contract, or
-detect whether the user has already payed for this resource by looking at the `repurchase_corelation_id`
-field in the contract. In the first case, the wallet stores `H_contract` in its local database.
-If there is a match, the wallet starts a IIG by visiting the fulfillment URL associated with the
-already-made payment (see next section)
+ detect whether the user has already payed for this resource by looking at the `repurchase_corelation_id`
+ field in the contract. In the first case, the wallet stores `H_contract` in its local database.
+ If there is a match, the wallet starts a IIG by visiting the fulfillment URL associated with the
+ already-made payment (see :ref:`ffil`)
3. The payment is asked to the merchant by visiting the fulfillment URL (which inficated in the
-Contract). Since the merchant keeps no state for any purchase, it needs relevant information
-in the fulfillment URL in order to reconstruct the contract and send the payment to the backend.
-This information is implicit in the mention of 'fulfillment URL'.
+ Contract). Since the merchant keeps no state for any purchase, it needs relevant information
+ in the fulfillment URL in order to reconstruct the contract and send the payment to the backend.
+ This information is implicit in the mention of 'fulfillment URL'.
4. When a fulfillment URL is visited, the merchant reconstructs the contract and sends back to
-the user the a `taler-execute-payment` event which embeds the following object
+ the user the a `taler-execute-payment` event which embeds the following object
- .. code-block:: tsref
+ .. code-block:: tsref
{
// base32 of the Contract's hashcode
@@ -117,15 +74,36 @@ the user the a `taler-execute-payment` event which embeds the following object
// URL where to send deposit permission
pay_url: string;
- // Used in the other IIG initiation (see next section)
+ // Used in 'IIG by fulfillment URL'
offering_url: string;
}
5. The wallet sends the deposit permission to `pay_url`
6. If the payment is successful, then the merchant sets the state for the bought
-item to `payed` and communicate the outcome to the wallet (see merchant API for
-involved HTTP codes and JSONs)
+ item to `payed` and communicate the outcome to the wallet (see :ref:`merchant API <pay>` for
+ involved HTTP codes and JSONs)
7. Finally, the wallet can visit again the fulfillment URL and get the payed resource
-thanks to the `payed` state
+ thanks to the `payed` state
+
+.. _ffil:
+
+------------------------
+IIG by `fulfillment` URL
+------------------------
+
+We stress again that the fulfillment URL contains all the information a merchant needs
+to reconstruct a contract.
+
+1. The user visits a fulfillment URL
+
+2. The merchant replies with the same data structure shown in point 4 above
+
+3. The wallet checks if `H_contract` already exists in its database. If it does not exist,
+ then the wallet will automatically visit the offering URL (by looking at the `uffering_url`
+ field) and all the process will restart as in point 1 above. Tipically, this occurs when a
+ user visits a fulfillment URL gotten from some other user. If `H_contract` is known, then the
+ wallet takes the associated deposit permission from its database and the process will continue
+ as from point 5 above. Please note that the latter scenario is not double spending since the
+ same coins are spent on the same contract.