About the web services API
This EOL v3 web services API is in its infancy. Suggestions welcome.
In order for you to be able to use the web services API, an EOL administrator needs to make you a "power user". Please contact hammockj AT si.edu
Getting a token
The API can be used directly in a browser, but to use it from a program (including a shell script) it is necessary to obtain a 'token'. The token is simply a string that holds encrypted information that tells the web services who you are.
For now, you need to get a token using a web browser. (The idea is that in the future you'll be able to get a token via a shell script or web service.)
To obtain a token, log in to your power user account and visit the page (Note: services is plural here since the token applies to all of the services.) Copy the token (without the quotes) from the web browser into a file, so you can use it in API calls. Keep the token in a safe place; it is similar to a password.
Invoking API methods
Individual API services all have URLs starting (singular).
Services are invoked using HTTPS.
With each request, it is necessary to provide the token in an HTTP Authorization: header, preceded by JWT. For example:
Authorization: JWT eyJ0eXAzczOzJZUzZ1NzJ9.eyJ1c2VyZjoTA1QWJsZzfQ.Xf5FSA2P_lJBGyBYGTsRPczAkg
Don't forget to use https: instead of http:, to keep the token private.
The manner in which you specify the addition of this header depends on the programming language. For examples see below.
If you store the token in a file, be sure to protect the file. On any Unix-like machine, you can do the following at the shell: (assume the file is called api.token)
chmod 600 api.token
Services can be used whenever an HTTPS client is available, e.g. from a web browser, using a command line tool such as curl or wget, or a library such as requests in python. See the documentation on using the API from various platformsfor a few examples.
The cypher service
Currently (November 2018) the only API service is /service/cypher. This service takes the following parameters via the usual CGI key=value convention.
- query - a Cypher query (see here)
- format - requests a particular output format
Two output formats are available:
- cypher (the default) - the JSON format natively returned by the neo4j Cypher query engine
- csv - comma separated values format, with a header row naming the returned variables listed in the query, and each subsequent row being a result record
A number of examples of queries against the traits database are provided. These example queries illustrate both the use of Cypher (the query language) and the use of the traits database schema.
- A LIMIT clause is required, in order to encourage you to put a cap on result set sizes (remember that small errors in a query might lead to enormous query result sets)
- Queries (commands) that would cause changes to the graph database are rejected: create, set, delete, and so on
This section is for those managing the EOL web site itself. Users of the API need not be concerned about this.
To enable token authentication, one must add a single line to the config/secrets.yml to set the json_web_token_secret. In my own (JAR's) debugging setup I do this under the development: section of the file by adding a line
For other installations it might have to go under a different section. I don't know how the key should be generated; I used a random 64-hex-digit string but maybe it doesn't have to be hex or so long.
Any change to this key will require 'power users' to get new tokens.