Allow for large json strings in webdriver response

Etaoin uses cheshire which uses jackson.
Jackson implemented, for security reasons, processing limits.
Starting with cheshire 6.0.0 these jackson limits are configurable.

The default json input string length for jackson is 20mb.
This is small for Etaoin, a webdriver will return a base64 encoded pdf
for a print page request.
We've bumped the json input string limit to ~2gb.

Closes #691

Author: lread

CHANGELOG.adoc

@@ -22,6 +22,8 @@ A release with an intentional breaking changes is marked with:
 * Changes
 ** Bumped deps.
 ({lread})
+** {issue}691[#691]: Allow for large json strings in webdriver responses
+({lread})
 ** {issue}696[#696]: Stop hiding json parse exceptions
 ({lread})
 ** {issue}676[#676]: Fix new driver creation so that it sidesteps some underlying Firefox race conditions and improves CI test stability. ({person}dgr[@dgr])

src/etaoin/impl/client.clj

@@ -2,6 +2,7 @@
   (:require
    [babashka.http-client :as client]
    [cheshire.core :as json]
+   [cheshire.factory :as cheshire-factory]
    [clojure.string :as str]
    [clojure.tools.logging :as log]
    [etaoin.impl.proc :as proc]
@@ -37,6 +38,12 @@
 ;;
 ;; helpers
 ;;
+(def ^:private default-jackson-factory
+  "The default jackson input string length is 20mb which is low for Etaoin.
+  For example a webdriver print page returns the page pdf as a base64 encoded string.
+  The current underlying jackson 2.8.3 option type is an `int` so we are effectively using the max
+  possible for this option (just under 2GiB)."
+  (cheshire-factory/make-json-factory {:max-input-string-length Integer/MAX_VALUE}))
 
 (defn- url-item-str [item]
   (cond
@@ -50,7 +57,11 @@
 
 (defn- parse-json [body]
   (let [body* (str/replace body #"Invalid Command Method -" "")]
-    (json/parse-string body* true)))
+    ;; override jackson options, prefer user specified binding
+    ;; (not officially supported but convenient for testing)
+    (binding [cheshire-factory/*json-factory* (or cheshire-factory/*json-factory*
+                                                  default-jackson-factory)]
+      (json/parse-string body* true))))
 
 (defn- error-response [body]
   (if (string? body)