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Python SDK for the real estate transaction standard (RETS)

Project description

RETSDK

A Python SDK for the Real Estate Transaction Standard (RETS)

Installation

pip install retsdk

Usage

Initialize a client

Create a new RETSConnection instance to connect to a RETS server.

Example
from retsdk.client import RETSConnection

rets = RETSConnection(
    username='your_rets_username',
    password='your_rets_password',
    login_url='https://rets.somemls.com/rets/Login/'
)

# Metadata info & transaction URLs get loaded automatically
print(rets.metadata_version)
# 1.00.00235

print(rets.metadata_timestamp)
# 2015-05-20T20:08:15Z

print(rets.min_metadata_timestamp)
# 2015-05-20T20:08:15Z

print(rets.get_metadata_url)
# https://rets.somemls.com/rets/GetMetadata/

print(rets.get_search_url)
# https://rets.somemls.com/rets/Search/

print(rets.get_object_url)
# https://rets.somemls.com/rets/GetObject/
Initialization Arguments
Argument Type Required Meaning
username String Yes RETS account username
password String Yes RETS account password
login_url String Yes RETS server login URL
auth_type String No Authentication type (defaults to 'digest')
rets_version String No Specifies the RETS version to be used (defaults to 'RETS/1.7.2')
user_agent String No Specifies the user-agent (defaults to 'RETSDK/1.0')

Download Metadata

There are (usually) several tiers of metadata to consider in a RETS system. These are resource metadata, class metadata, table metadata, and lookup-type metadata. RETSDK has methods to work with each of these programmatically, but if you would like to view metadata right in your browser with no additional setup, you can also try RETSMD.

All of the metadata query methods return a response dictionary with the following items:

Key Meaning Value
more_rows Indicates whether there are more rows to download Boolean
ok Indicates whether the process completed successfully Boolean
record_count The number of rows returned Integer
reply_code The server's RETS reply code Integer
reply_text The message accompanying the RETS reply code String
rows The metadata records returned by the server List

1. Resource Metadata

Resource metadata is the top layer of metadata; it tells you what resources are accessible from your account. Use the get_resource_metadata() method to download resource metadata.

Arguments

None

Example
# Get the RETS system's resource metadata
response = rets.get_resource_metadata()

from pprint import pprint
pprint(response)
#{'more_rows': False,
# 'ok': True,
# 'record_count': 2,
# 'reply_code': '0',
# 'reply_text': 'Operation Success.',
# 'rows': [{'ClassCount': 1,
#           'ClassDate': '2015-01-28T21:06:04Z',
#           'ClassVersion': '1.00.00001',
#           'Description': 'Agent',
#           'KeyField': 'sysid',
#           'LookupDate': '2015-01-21T17:31:54Z',
#           'LookupVersion': '1.00.00001',
#           'ObjectDate': '2014-03-21T17:15:24Z',
#           'ObjectVersion': '1.00.00001',
#           'ResourceID': 'Agent',
#           'StandardName': 'Agent',
#           'TableName': 'Agent',
#           'VisibleName': 'Agent'},
#          {'ClassCount': 1,
#           'ClassDate': '2015-01-28T16:19:02Z',
#           'ClassVersion': '1.00.00001',
#           'Description': 'Listing',
#           'KeyField': 'sysid',
#           'LookupDate': '2015-01-28T14:34:35Z',
#           'LookupVersion': '1.00.00001',
#           'ObjectDate': '2015-01-28T14:34:35Z',
#           'ObjectVersion': '1.00.00001',
#           'ResourceID': 'Property',
#           'StandardName': 'Property',
#           'TableName': 'Listing',
#           'VisibleName': 'Listing'}]}

2. Class Metadata

Class metadata provides information about the classes in a resource. Use the get_class_metadata() method to get class metadata.

Arguments
Argument Name Required Meaning
resource No The ID of a RETS resource. Defaults to 'Property'.
Example
class_metadata_response = rets.get_class_metadata(resource='Property')

pprint(class_metadata_response)
#{'more_rows': False,
# 'ok': True,
# 'record_count': 1,
# 'reply_code': '0',
# 'reply_text': 'Operation Success.',
# 'rows': [{'ClassName': 'Listing',
#           'Description': 'Cross Property',
#           'StandardName': None,
#           'TableDate': '2015-01-28T02:49:39Z',
#           'TableVersion': '1.00.00985',
#           'UpdateDate': '2015-01-28T14:32:06Z',
#           'UpdateVersion': '1.00.00001',
#           'VisibleName': 'Cross Property'}]}

3. Table Metadata

Table metadata tells you about the specific fields available in a class. Use the get_table_metadata() method to get table metadata.

Arguments
Argument Name Required Meaning
resource No The ID of a resource. Defaults to 'Property'.
class_name No The class name or system name of a class within a resource. Defaults to 'Listing'.
Example
table_metadata_response = rets.get_table_metadata(
    resource='Property', 
    class_name='Listing'
)

pprint(table_metadata_response)
#{'more_rows': False,
# 'ok': True,
# 'record_count': 2,
# 'reply_code': '0',
# 'reply_text': 'Operation Success.',
# 'rows': [{'Alignment': 'Left',
#           'DBName': 'price',
#           'DataType': 'Int',
#           'Default': None,
#           'InKeyIndex': 0,
#           'Index': 1,
#           'Interpretation': 'Number',
#           'LongName': 'Price',
#           'LookupName': None,
#           'MaxSelect': None,
#           'Maximum': 2147483647,
#           'MaximumLength': 11,
#           'MetadataEntryID': 200,
#           'Minimum': -2147483648,
#           'Precision': None,
#           'Required': 1,
#           'Searchable': 1,
#           'ShortName': 'Price',
#           'StandardName': 'Price',
#           'SystemName': 'Price',
#           'Unique': 0,
#           'Units': 'USD',
#           'UseSeparator': None},
#          {'Alignment': 'Left',
#           'DBName': 'property_type',
#           'DataType': 'Character',
#           'Default': None,
#           'InKeyIndex': 0,
#           'Index': 1,
#           'Interpretation': 'Lookup',
#           'LongName': 'Property Type',
#           'LookupName': 'PropertyType',
#           'MaxSelect': None,
#           'Maximum': None,
#           'MaximumLength': 32,
#           'MetadataEntryID': 201,
#           'Minimum': None,
#           'Precision': None,
#           'Required': 1,
#           'Searchable': 1,
#           'ShortName': 'PropertyType',
#           'StandardName': 'PropertyType',
#           'SystemName': 'PropertyType',
#           'Unique': 0,
#           'Units': None,
#           'UseSeparator': None}]}

4. Lookup-Type Metadata

The last type of metadata data to consider is lookup-type metdata. If a field in the table metadata has an interpretation of "Lookup", there is a list of specific values that the field can hold. Get this list of values with the get_lookup_type_metadata() method.

Arguments
Argument Name Required Meaning
resource No The ID of a resource. Defaults to 'Property'.
lookup_name Yes A field's lookup name.
Example
lookup_type_metadata_response = rets.get_lookup_type_metadata(
    resource='Property',
    lookup_name='PropertyType'
)

pprint(lookup_type_metadata_response)
# {'more_rows': False,
#  'ok': True,
#  'record_count': 3,
#  'reply_code': '0',
#  'reply_text': 'Operation Success.',
#  'rows': [{'LongValue': 'Single Family Detached',
#           'MetadataEntryID': 10002,
#           'ShortValue': 'SFD',
#           'Value': 'SFD'},
#          {'LongValue': 'Condominium',
#           'MetadataEntryID': 10003,
#           'ShortValue': 'CON',
#           'Value': 'CON'},
#          {'LongValue': 'Multifamily',
#           'MetadataEntryID': 10004,
#           'ShortValue': 'MUL',
#           'Value': 'MUL'}]}

Download Data

Download data or search through records using the get_data() method. You will need to specify a query (using DMQL) and a list of the fields that you would like to have returned to you (see Download Metadata to learn how to find out what fields are available).

Arguments
Argument Name Required Meaning
resource Yes The ID of a RETS system resource.
class_name Yes The name of a class in the specified resource.
query Yes A DMQL query
fields Yes A list of the fields to be returned
data_format No The RETS data format to be used with fields. Defaults to 'COMPACT-DECODED'.
limit No The maximum number of records to return
offset No An offset position that can be used with limit
Response Dictionary
Key Meaning Value Type
more_rows Indicates whether there are more rows to download for the current query Boolean
ok Indicates whether the query was processed successfully Boolean
record_count The number of rows returned Integer
reply_code The server's RETS reply code Integer
reply_text The message accompanying the RETS reply code String
rows The actual records returned by the query List
Examples
# Query all listings with "SFD" PropertyType, return only MLSNumber and Price
rets_query = "(PropertyType=SFD)"
fields_to_be_downloaded = ["MLSNumber", "Price"]

data = rets.get_data(
    resource='Property',
    class_name='Property',
    query=query,
    fields=fields_to_be_downloaded,
)

pprint(data)
# {'more_rows': False,
#  'ok': True,
#  'record_count': '10',
#  'reply_code': '0',
#  'reply_text': 'Operation Success.',
#  'rows': [{'Price': 199000.0, 'MLSNumber': 'MLS0000001'},
#           {'Price': 2500000.0, 'MLSNumber': 'MLS0000002'},
#           {'Price': 319500.0, 'MLSNumber': 'MLS0000003'},
#           {'Price': 275900.0, 'MLSNumber': 'MLS0000004'},
#           {'Price': 239900.0, 'MLSNumber': 'MLS0000005'},
#           {'Price': 339900.0, 'MLSNumber': 'MLS0000006'},
#           {'Price': 249900.0, 'MLSNumber': 'MLS0000007'},
#           {'Price': 219900.0, 'MLSNumber': 'MLS0000008'},
#           {'Price': 579900.0, 'MLSNumber': 'MLS0000009'},
#           {'Price': 209900.0, 'MLSNumber': 'MLS0000010'}]}

You may optionally use the limit and offset parameters to page the data that you want to download. This allows you to break large downloads into smaller pieces.

# A broader RETS query that might returns lots of records
rets_query=(PropertyType=SFD,CON,MUL)
fields_to_be_downloaded = ["MLSNumber", "Price"]

# Use a loop to download 10 records at a time
download_complete = False
last_offset = 0
while not download_complete:
    data = rets.get_data(
        resource='Property',
        class_name='Listing',
        query=rets_query,
        fields=fields_to_be_downloaded,
        limit=10,
        offset=last_offset
    )

    for row in data['rows']:
        # Do something with the rows you downloaded here (save to a database, etc.)
        pass

    if data['more_rows']:
        # Still more to download!
        last_offset += 10
    else:
        # Done!
        download_complete = True

Getting a Record Count without Returning Data

If you just want a count of how many records match your query, you can use get_count() instead of get_data(). get_count() will return an integer instead of a full response dictionary.

You do not specify fields, limit, or offset with get_count(), but otherwise it works just like get_data(). It is, in fact, just another wrapper for the RETS Search transaction with the Count parameter set differently.

Example
row_count = rets.get_count(
    'Property',
    class_name='Property',
    query=rets_query
)

print(row_count)
# 105

Download Images

Use the get_object() method to download images. This method is a wrapper for the RETS specification's GetObject transaction.

get_object() returns a response dictionary, but the dictionary does not contain 'rows', 'record_count' or 'more_rows'. Instead, it will contain an item called 'object_data', where the actual object data will be stored as bytes.

Arguments
Argument Name Required Meaning
resource Yes The ID of a RETS system resource.
obj_type Yes The type of object to be returned (e.g., 'Photo').
obj_id Yes The system ID of the record associated with object.
order_no No The order number of the image or other object (for situations where there are multiple images associated with one listing)
path No A file system path where image data should be written (used only when write=True).
write No A boolean value that can optionally be set to True if you would like get_object() to write image/object data to a file for you. You must specifiy a path if you wish to use this option.
Response Dictionary:
Key Meaning Value Type
ok Indicates whether the object download was successful Boolean
reply_code The server's RETS reply code Integer
reply_text The message accompanying the RETS reply code String
object_data The object data payload Bytes
Example
# Download an image (as bytes)
img_response = rets.get_object(
    resource='Property',
    obj_type='Photo',
    obj_id='MLS0000001',
    order_no=0
)

# Write the image data to a file somewhere
path = "/tmp/rets/images/MLS0000001_01.jpg"
if img_response['ok']:
    with open(path, 'wb') as f:
        f.write(img_response['object_data'])

Logout

If you would like to, you can close your RETS session with the logout() method.

Arguments

None

Response Dictionary:
Key Meaning Value Type
more_rows Indicates whether there are more rows to download for the current transaction Boolean
ok Indicates whether the transaction was successful Boolean
record_count The number of rows returned Integer
reply_code The server's RETS reply code Integer
reply_text The message accompanying the RETS reply code String
rows The actual records returned by the logout transaction List
Example
logout_response = rets.logout()

pprint(logout_response)
# {'more_rows': False,
#  'ok': True,
#  'record_count': 1,
#  'reply_code': '0',
#  'reply_text': 'Operation Success.',
#  'rows': [{'SignOffMessage': 'Connection Closed'}]}

Exceptions

RETSDK raises these exceptions when stuff goes wrong:

Exception Meaning
retsdk.exceptions.AuthenticationError Raised when an unsupported authentication type is specified during intialization
retsdk.exceptions.RequestError Raised if a RETS transaction request cannot be completed
retsdk.exceptions.TransactionError Raised if the user attempts to perform a transaction that is not supported by the current RETS account.

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