Add developer documentation for EPP

docs/developer/registry-access.md

@@ -0,0 +1,101 @@
+# Working with the registry via EPP
+
+## Overview of parts
+
+**EPP** is the protocol which describes how a registry and registrar communicate with XML over a TCP socket connection.
+
+**epplib** is a Python library implementation of the TCP socket connection. It has helper functions and dataclasses which can be used to send and receive the XML messages.
+
+**epplibwrapper** is a module in this repository which abstracts away the details of authenticating with the registry. It assists with error handling by providing error code constants and an error class with some helper methods.
+
+**Domain** is a Python class. It inherits from `django.db.models.Model` and is therefore part of Django's ORM and has a corresponding table in the local registrar database. Its purpose is to provide a developer-friendly interface to the registry based on *what a registrant or analyst wants to do*, not on the technical details of EPP.
+
+## Debugging in a Python shell
+
+You'll first need access to a Django shell in an environment with valid registry credentials. For example:
+
+```shell
+cf ssh getgov-ENVIRONMENT
+/tmp/lifecycle/shell  # this configures your environment
+./manage.py shell
+```
+
+You'll next need to import some code.
+
+```
+from epplibwrapper import CLIENT as registry, commands
+from epplib.models import common
+```
+
+Finally, you'll need to craft a request and send it.
+
+```
+request = ...
+response = registry.send(request)
+```
+
+See below for some example commands to send. Replace example data with data which makes sense for your debugging scenario. Other commands are available; see the source code of epplib for more options.
+
+
+### Get info about a contact
+
+```
+request = commands.InfoContact(id='sh8013')
+```
+
+### Create a new contact
+
+```
+DF = common.DiscloseField
+di = common.Disclose(flag=False, fields={DF.FAX, DF.VOICE, DF.ADDR}, types={DF.ADDR: "loc"})
+addr = common.ContactAddr(street=['123 Example Dr.'], city='Dulles', pc='20166-6503', cc='US', sp='VA')
+pi = common.PostalInfo(name='John Doe', addr=addr, org="Example Inc.", type="loc")
+ai = common.ContactAuthInfo(pw='feedabee')
+
+request = commands.CreateContact(id='sh8013', postal_info=pi, email='jdoe@example.com', voice='+1.7035555555', fax='+1.7035555556', auth_info=ai, disclose=di, vat=None, ident=None, notify_email=None)
+```
+
+### Create a new domain
+
+```
+ai = common.DomainAuthInfo(pw='feedabee')
+request = commands.CreateDomain(name="okay.gov", registrant="sh8013", auth_info=ai)
+```
+
+### Create a host object
+
+```
+request = commands.CreateHost(name="ns1.okay.gov", addrs=[common.Ip(addr="127.0.01"), common.Ip(addr="0:0:0:0:0:0:0:1", ip="v6")])
+```
+
+### Check if a host is available
+
+```
+request = commands.CheckHost(["ns2.okay.gov"])
+```
+
+### Update a domain
+
+```
+request = commands.UpdateDomain(name="okay.gov", add=[common.HostObjSet(["ns1.okay.gov"])])
+```
+
+```
+request = commands.UpdateDomain(name="okay.gov", add=[common.DomainContact(contact="sh8014", type="technical")])
+```
+
+### How to see the raw XML
+
+To see the XML of a command before the request is sent, call `request.xml()`.
+
+To see the XML of the response, you must send the command using a different method.
+
+```
+registry._client.connect()
+registry._client.send(registry._login)
+
+request = commands.InfoDomain(name="ok.gov")
+
+registry._client.transport.send(request.xml())
+response = registry._client.transport.receive()
+```