askCO 1.0.2

Python interface for Te Papa's collections API

askCO: search and query records from Te Papa's collections API

This script provides an interface for getting data from the Museum of New Zealand Te Papa Tongarewa. With it, you can run searches and request individual records, which are returned as JSON.

See the API documentation for what's available and how to construct searches.

Te Papa's API requires a registration key in the headers of each request – go to https://data.tepapa.govt.nz/docs/register.html to register. I recommend adding the API key to an environment variable called 'TE-PAPA-KEY', and then calling that from your script to pass to askCO.

Install and run

Install using pip: pip install askCO

askCO requires the requests module.

To run a query, import the AskCO class, initialise it with your API key, and call the get_single_record() or get_search_results() methods with the necessary parameters.

Try running a query

The tryCO.py file provides some prepared queries using search, scroll and various resource endpoints. It calls the API key, sets functional and query parameters, and sets up then runs the request.

You can also enter your own parameters to try out different queries.

Types of query

Record

You can get a single record by providing an endpoint and the record's id number.

This will return all the published metadata for the record, such as its title, description, and any associated images.

You can find a record's id number by searching with the API or on Collections Online. In the API, it's in the id field, and on CO it's at the end of the record's URL.

This record's id is 1058008

This kind of query doesn't need any extra parameters.

Related records

You can check any record to see what other records it's related to. For example, the record for an artist will be related to their artworks.

Like a record query, you provide an endpoint and record id number, but because it's a kind of search you can also add some parameters.

The most useful parameter is types, which lets you filter the related records to just what you want. If you want to see an artist's related people but not their artworks, you can set types to Person.

Searching and scrolling

There are two ways to search for records, search and scroll. Both kinds of search return all the same information as if you requested each record by itself.

The search query mode is what you're usually going to want to use. You can set a search term, various kinds of filters, and specify what fields you want returned. By default, it returns 100 records per page.

scroll is good to use when you want to harvest all the available records for your search, such as when you want to export and process the results. The initial query is a lot like a regular search, but the following pages are retrieved by pinging a special URL until all records have been returned. scroll also defaults to 1000 records per page.

Both search modes return all available records (up to 50,000 for search), but you can apply a record_limit to avoid getting more data than you need.

Parameters

Functional parameters

When initialising the AskCO class, you need to provide you api_key. This will be used to generate the needed authentication headers.

You can also set:

• base_url: defaults to https://data.tepapa.govt.nz/collection
• quiet: defaults to True

All queries require the following parameter.

• query_mode: record, related, scroll, or search

You can also set:

• method: defaults to POST for scroll, otherwise GET, and you can also set this to HEAD
• record_limit: On related, scroll, or search, the maximum number of records to return
• attempts: How many times to retry a failing query. Defaults to 3
• timeout: A tuple used to set an extending delay before timing out. Defaults to (0.5, 3)

Query parameters

A record query only requires two parameters:

• endpoint
• record_id

For search queries endpoint is optional, but if you don't specify one you'll get results for all kinds of record. record_id is used for related but not search or scroll.

The valid endpoints are:

• agent
• category
• document
• fieldcollection
• group
• media
• object
• place
• scroll (can't be used for record or related)
• search (can't be used for record or related)
• taxon
• topic

Search queries also have a params parameter, which are the values that appear after the ? in the query URL.

These include:

• query: Your search term, which is joined to any filters you provide. Defaults to "*"
• size: How many records you want to return in a page. Defaults to 100 for search and related, and 1000 for scroll
• filters: See below. Defaults to no filters
• facets: Not yet implemented
• fields: Which fields to return - useful if you know exactly what you need. Defaults to all available fields
• from: Used when paging through results, but can be manually set if you want to skip ahead
• sort: How to order your results - for example, "meta.modified" sorts by oldest first, and "-meta.modified" sorts by newest first. Defaults to the API's quality score
• types: Used for related queries, letting you filter to particular kinds of records, eg Object, Person, Category
• duration: Used for scroll queries, the length of time the scroll endpoint is kept alive in minutes. Defaults to 1 minute

Query filters

On search and scroll queries you can filter your search results by adding fields and values to the filters parameter.

Some of the most useful filters are:

• collection: eg Art, PacificCultures, FossilVertebrates
• type: the main type of the record, eg Object, Specimen, Person
• additionalType: a more narrowly-defined type, eg PreservedSpecimen on a Specimen record
• identifier: the registration number for the item, eg RB001679 - helpful when you want to find a record but don't know its id number
• hasRepresentation.rights.allowsDownload: set to "true" to only return records with images that can be downloaded

Set up your filters as a list of dictionaries:

"filters": [
    {"type": "equals",
     "field": "collection",
     "value": "Photography"},
    {"type": "equals",
     "field": "hasRepresentation.rights.title",
     "value": "No Known Copyright"}
     ]

Filters get applied as AND predicates by default, but you can use others, as well as nest predicates.

"filters": [
    {"type": "in",
     "field": "collection",
     "value": [
        "Plants",
        "Photography"]
        },
    {"type": "not",
     "predicate": 
        {"type": "equals",
         "field": "_exists_",
         "value": "hasRepresentation"}
         }
    ]

When you supply a list of values with an IN predicate, they'll be sent through as a series of OR statements for that field.

Boolean filter values get turned into strings to make them work, and string values get put in quotes. This also lets you use spaces, slashes, and other special characters in your filter values.

Keep in mind that not all fields can be filtered - most nested fields like production.contributor.title or identification.toTaxon.qualifiedName aren't indexed to allow this. However, the values are still used when searching in general so you can include them in your query.

Query facets

Faceting is not implemented in askCO yet.

Faceting with the Te Papa API

Returned objects

Individual record queries return both the Requests response object and the JSONified data.

response, record = askco.get_single_record(endpoint="object", record_id=123456...)

Search queries yield each page of results, providing the Requests response object and the JSONified results.

for response, results in askco.get_search_results(endpoint="object", params={"query": "cat", "filters"...}...):
    # process each page of results

The results JSON can be easily split into parts:

records = results.get("results")
facets = results.get("facets")
metadata = results.get("_metadata")

This gives you access to all the details of the Requests response, while also making it easy to work directly with the data.