cascade-cms

A typed, async REST client for Hannon Hill Cascade CMS.

Full Documentation

Usage

from cascade_cms.cmstypes import Asset, IdentifierType
from cascade_cms.wrapper import CascadeWrapperBase

environment_variables = {
    "API_KEY": "...",
    "CASCADE_URL": "...",
    "SERVER": "prod",  # label used for logfile naming
}

with CascadeWrapperBase(environment_variables) as cascade:
    identifier = IdentifierType(identifier="e868f539ac1001062cfa029c4c5df4d0", asset_type="folder")
    cascade.operations.read(identifier)
    results = cascade.submit_requests(Asset)

Operations that take an identifier (read, delete, copy, move, publish, checkIn, checkOut, listSubscribers, readAccessRights, readWorkflowSettings, readWorkflowInformation, performWorkflowTransition) accept either an IdentifierType (asset type + UUID) or a Path (asset type + site name + site-relative path) — see cascade_cms.cmstypes.resolve_identifier.

See examples/read_and_update_asset.py for a fuller walkthrough.

Operation chains

Every cascade.operations.<op>() call starts an operation chain and returns it. Chaining .then(callback) or another operation onto it adds a step to that chain; a fresh cascade.operations.<op>() call starts a separate one.

Steps inside a chain run strictly in order, each receiving the previous step's result, so a read can be transformed and written back in one pass:

def rewrite(asset):
    asset.keywords = "updated"
    return asset

with CascadeWrapperBase(environment_variables) as cascade:
    cascade.operations.read(page_a).edit(page_a, rewrite).publish(page_a)
    cascade.operations.read(page_b).then(report)
    cascade.operations.delete(old_page)

    results = cascade.submit_requests()

• Chains run concurrently, so a batch still costs one round of requests, not one per chain. Only the steps within a chain are sequential.
• One result per chain, in the order the chains were built — results[0] belongs to the first chain. No more matching responses back to requests by hand.
• Failures are values, not gaps. A chain stops at its first failure and that object lands in the results: a CascadeError when the API rejects a request, or the exception a callback raised. Other chains are unaffected. submit_requests() returns a ChainResults — still a list, in that same chain-creation order — with .success (results from chains that didn't fail) and .failed (a ChainFailure per failed chain, naming the exact step and its category) added. There's no need for an isinstance(result, CascadeError) check or a try/except around submit_requests() — CascadeWrapperBase owns whether a failure ends the script; see "Error handling" below.
• A callback returning None passes the previous result through, so side-effect callbacks (logging, reporting) don't break the chain.
• edit() accepts a callable as its payload; it is invoked with the previous step's result, which is how a transformed asset gets written back.
• Chains are cleared once submit_requests() returns, so a callback registered for one batch never re-runs in the next.

Error handling

Failure handling lives in the library, not in your script. CascadeWrapperBase's context manager owns it end to end:

• No try/except around submit_requests(), and no isinstance() checks in your script — read .success/.failed off the ChainResults it returns instead.
• If the batch itself breaks (not an individual chain — e.g. the driver's event loop fails), submit_requests() raises CascadeBatchError rather than returning an empty list.
• At with-block exit, with exit_on_failure=True (the default), any recorded failure ends the script with a non-zero exit code — code written after the with block does not run in that case. A callback exception is re-raised unwrapped (plain traceback); a CascadeError/network/library-side failure raises SystemExit(1) with no extra traceback, since it was already logged.
• Pass exit_on_failure=False to embed the wrapper in a longer-lived process (e.g. an MCP server) — __exit__ then never raises; read .success/.failed off the results yourself.
• The logfile's !ERROR: line is prefixed [NETWORK] for a network-layer failure or [CASCADE-REST-CMS] for any other library-side failure; a CascadeError or a callback exception gets no prefix. A batch-level failure takes the prefix that matches its cause.
• Cascade always answers HTTP 200 with a JSON body; a non-200 status (an HTML page from the server layer, e.g. 501 Not Implemented) is reported as a CascadeError whose message is the status code and reason. The HTML body is never read or logged.
• At exit, the console always prints a tally: "{failed} failed, {succeeded} succeeded", cumulative across every submit_requests() call in the session, with ": reference log for details" appended only when at least one failure came from the API, the network, or the library itself (not from a callback-only failure). The tally is also written to the logfile.

with CascadeWrapperBase(environment_variables) as cascade:
    cascade.operations.read(identifier)
    results = cascade.submit_requests(Asset)
    for asset in results.success:
        ...  # only successful reads
# If anything failed, execution never reaches here — the with block already
# raised (or exited) on the way out.

Logging

CascadeWrapperBase accepts an optional second debug argument. Leaving it as None (the default) runs in normal mode: a minimal console ([INIT]/[LOG]/[RUNNING]/n/N succeeded/ [DONE]/[EXIT]) plus a simple logfile at ./logs/{SERVER}_{timestamp}_{n}.log. Passing a dict switches to debug mode: a quiet console and a verbose, nested logfile at ./logs/{SERVER}_debug_{timestamp}_{n}.log describing every request, response, callback, and error. Each wrapper gets its own file, even when two are created in the same second.

• Status lines go to stderr, not stdout ([INIT], [LOG], [DONE], the tally, [EXIT], console [ERROR] lines), so stdout stays free for your script's own output.
• [LOG]: <path> is printed right after [INIT], giving the path of this run's logfile.
• log_dir= (keyword-only) sets the log directory in normal and debug mode; it is created if missing and defaults to ./logs. If a debug config also sets log_dir, the parameter wins.
• [EXIT-CODE]: is the last line written to the logfile: 0 for a clean run, 1 when the script ends with a failure, 1 (callback exception: <Type>) / 1 (uncaught exception: <Type>) when an exception ends it, or n/a (exit_on_failure disabled). Read the logfile for the tally and exit code rather than capturing console output.
• In debug mode with show_network_headers, the Authorization header is masked to its last four characters (Bearer ****abcd).

debug_config = {
    "log_dir": "./logs",
    "log_operations": True,
    "log_callbacks": True,
    "log_responses": True,
    "show_payload_data": True,
    "show_network_headers": False,
    "show_error_variables": True,
    "response_line_limit": 8,   # -1 = dump full response body
}

with CascadeWrapperBase(environment_variables, debug=debug_config) as cascade:
    ...

All keys are required in debug mode — there are no inferred defaults, so you always know what you opted into.

Development

pip install -e ".[dev]"
pytest