dog-and-duck/src/dog_and_duck/quack/picky/utils.clj
Simon Brooke 25c86b80fa
Collections validation written, refactoring done, existing tests pass.
New tests have yet to be written for collections functionality.
2022-12-27 20:28:27 +00:00

320 lines
12 KiB
Clojure

(ns dog-and-duck.quack.picky.utils
"Utility functions supporting the picky validator"
(:require [clojure.data.json :as json]
[clojure.set :refer [intersection]]
[dog-and-duck.quack.picky.constants :refer [activitystreams-context-uri
actor-types
context-key severity-filters
validation-fault-context-uri
verb-types]]
[dog-and-duck.quack.picky.control-variables :refer [*reify-refs*]]
[dog-and-duck.quack.picky.fault-messages :refer [messages]]
[dog-and-duck.utils.process :refer [get-hostname get-pid]]
[taoensso.timbre :as log :refer [warn]])
(:import [java.net URI URISyntaxException]))
;;; Copyright (C) Simon Brooke, 2022
;;; This program is free software; you can redistribute it and/or
;;; modify it under the terms of the GNU General Public License
;;; as published by the Free Software Foundation; either version 2
;;; of the License, or (at your option) any later version.
;;; This program is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;; You should have received a copy of the GNU General Public License
;;; along with this program; if not, write to the Free Software
;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
(defn actor-type?
"Return `true` if the `x` is a recognised actor type, else `false`."
[^String x]
(if (actor-types x) true false))
(defn truthy?
"Return `true` if `x` is truthy, else `false`. There must be some more
idiomatic way to do this?"
[x]
(if x true false))
(defn has-type?
"Return `true` if object `x` has type `type`, else `false`.
The values of `type` fields of ActivityStreams objects may be lists; they
are considered to have a type if the type token is a member of the list."
[x type]
(assert (map? x) (string? type))
(let [tv (:type x)]
(cond
(coll? tv) (truthy? (not-empty (filter #(= % type) tv)))
:else (= tv type))))
(defn object-or-uri?
"Very basic check that `x` is either an object or a URI."
[x]
(try
(cond (string? x) (uri? (URI. x))
(map? x) (if (and (:type x) (:id x)) true false)
:else false)
(catch URISyntaxException _ false)
(catch NullPointerException _ false)))
(defmacro link-or-uri?
"Very basic check that `x` is either a link object or a URI."
[x]
`(if (object-or-uri? ~x) (has-type? ~x "Link") false))
(defn verb-type?
"`true` if `x`, a string, represents a recognised ActivityStreams activity
type."
[^String x]
(if (verb-types x) true false))
(defn has-activity-type?
"Return `true` if the object `x` has a type which is an activity type, else
`false`."
[x]
(let [tv (:type x)]
(cond
(coll? tv) (truthy? (not-empty (filter verb-type? tv)))
:else (verb-type? tv))))
(defn has-actor-type?
"Return `true` if the object `x` has a type which is an actor type, else
`false`."
[x]
(let [tv (:type x)]
(cond
(coll? tv) (truthy? (not-empty (filter actor-type? tv)))
:else (actor-type? tv))))
(defn filter-severity
"Return a list of reports taken from these `reports` where the severity
of the report is greater than this or equal to this `severity`."
[reports severity]
(cond (nil? reports) nil
(and
(coll? reports)
(every? map? reports)
(every? :severity reports)) (remove
#((severity-filters severity) (:severity %))
reports)
:else
(throw
(ex-info
"Argument `reports` was not a collection of fault reports"
{:arguments {:reports reports
:severity severity}}))))
(defn context?
"Returns `true` iff `x` quacks like an ActivityStreams context, else false.
A context is either
1. the URI (actually an IRI) `activitystreams-context-uri`, or
2. a collection comprising that URI and a map."
[x]
(cond
(nil? x) false
(string? x) (and (= x activitystreams-context-uri) true)
(coll? x) (and (context? (first (remove map? x)))
(= (count x) 2)
true)
:else false))
(defmacro has-context?
"True if `x` is an ActivityStreams object with a valid context, else `false`."
[x]
`(context? (context-key ~x)))
(defn make-fault-object
"Return a fault object with these `severity`, `fault` and `narrative` values.
An ActivityPub object MUST have a globally unique ID. Whether this is
meaningful depends on whether we persist fault report objects and serve
them, which at present I have no plans to do."
;; TODO: should not pass in the narrative; instead should use the :fault value
;; to look up the narrative in a resource file.
[severity fault]
(assoc {}
context-key validation-fault-context-uri
:id (str "https://"
(get-hostname)
"/fault/"
(get-pid)
":"
(inst-ms (java.util.Date.)))
:type "Fault"
:severity severity
:fault fault
:narrative (or (messages fault)
(do
(warn "No narrative provided for fault token " fault)
(str fault)))))
(defmacro nil-if-empty
"if `x` is an empty collection, return `nil`; else return `x`."
[x]
`(if (and (coll? ~x) (empty? ~x)) nil
~x))
(defn concat-non-empty
"Quick function to replace the pattern (nil-if-empty (remove nil? (concat ...)))
which I'm using a lot!"
[& lists]
(nil-if-empty (remove nil? (apply concat lists))))
(defn has-type-or-fault
"If object `x` has a `:type` value which is `acceptable`, return `nil`;
else return a fault object with this `severity` and `token`.
`acceptable` may be passed as either nil, a string, or a set of strings.
If `acceptable` is `nil`, no type specific tests will be performed."
[x acceptable severity token]
(when acceptable
(let [tv (:type x)]
(when-not
(cond
(and (string? tv) (string? acceptable)) (= tv acceptable)
(and (string? tv) (set? acceptable)) (acceptable tv)
(and (coll? tv) (string? acceptable)) ((set tv) acceptable)
(and (coll? tv) (set? acceptable)) (not-empty
(intersection (set tv) acceptable))
:else
(throw (ex-info "Type value or `acceptable` argument not as expected."
{:arguments {:x x
:acceptable acceptable
:severity severity
:token token}})))
(make-fault-object severity token)))))
(defn any-or-faults
"Return `nil` if validating one of these options returns `nil`; otherwise
return a list comprising a fault report object with this `severity-if-none`
and this token followed by all the fault reports from validating each
option.
There are several places - but especially in validating collections - where
there are several different valid configurations, but few or no properties
are always required."
[options severity-if-none token]
(let [faults (filter empty? options)]
(when (empty? faults)
;; i.e. there was at least one option that returned no faults...
(cons (make-fault-object severity-if-none token) faults))))
(defmacro cond-make-fault-object
"If `v` is `false` or `nil`, return a fault object with this `severity` and `token`,
else return nil."
[v severity token]
`(when-not ~v (make-fault-object ~severity ~token)))
(defn string-or-fault
"If this `value` is not a string, return a fault object with this `severity`
and `token`, else `nil`. If `pattern` is also passed, it is expected to be
a Regex, and the fault object will be returned unless `value` matches the
`pattern`."
([value severity token]
(when-not (string? value) (make-fault-object severity token)))
([value severity token pattern]
(when not (and (string? value) (re-matches pattern value))
(make-fault-object severity token))))
(defn object-faults
"Return a list of faults found in object `x`, or `nil` if none are.
If `expected-type` is also passed, verify that `x` has `expected-type`.
`expected-type` may be passed as a string or as a set of strings. Detailed
verification of the particular features of types is not done here."
([x]
(nil-if-empty
(remove empty?
(list
(when-not (map? x)
(make-fault-object :critical :not-an-object))
(when-not
(has-context? x)
(make-fault-object :should :no-context))
(when-not (:type x)
(make-fault-object :minor :no-type))
(when-not (and (map? x) (contains? x :id))
(make-fault-object :minor :no-id-transient))))))
([x expected-type]
(concat-non-empty
(object-faults x)
(when expected-type
(list
(has-type-or-fault x expected-type :critical :unexpected-type))))))
(defn object-reference-or-faults
"If this `value` is either
1. an object of `expected-type`;
2. a URI referencing an object of `expected-type`; or
3. a link object referencing an object of `expected-type`
and no faults are returned from validating the linked object, then return
`nil`; else return a sequence comprising a fault object with this `severity`
and `token`, prepended to the faults returned.
As with `has-type-or-fault` (q.v.), `expected-type` may be passed as a
string, as a set of strings, or `nil` (indicating the type of the
referenced object should not be checked).
**NOTE THAT** if `*reify-refs*` is `false`, referenced objects will not
actually be checked."
[value expected-type severity token]
(let [faults (cond
(string? value) (try (let [uri (URI. value)
object (when *reify-refs*
(json/read-str (slurp uri)))]
(when object
(object-faults object expected-type)))
(catch URISyntaxException _
(make-fault-object severity token)))
(map? value) (if (has-type? value "Link")
(cond
;; if we were looking for a link and we've
;; found a link, that's OK.
(= expected-type "Link") nil
(and (set? expected-type) (expected-type "Link")) nil
(nil? expected-type) nil
:else
(object-reference-or-faults
(:href value) expected-type severity token))
(object-faults value expected-type))
:else (throw
(ex-info
"Argument `value` was not an object or a link to an object"
{:arguments {:value value}
:expected-type expected-type
:severity severity
:token token})))]
(when faults (cons (make-fault-object severity token) faults))))
(defn coll-object-reference-or-fault
"As object-reference-or-fault, except `value` argument may also be a list of
objects and/or object references."
[value expected-type severity token]
(cond
(map? value) (object-reference-or-faults value expected-type severity token)
(coll? value) (concat-non-empty
(map
#(object-reference-or-faults
% expected-type severity token)
value))
:else (throw
(ex-info
"Argument `value` was not an object, a link to an object, nor a list of these."
{:arguments {:value value}
:expected-type expected-type
:severity severity
:token token}))))