Add tooling API

README.md

@@ -2,10 +2,10 @@ Current [semantic](http://semver.org/) version:
 
 ```clojure
 [com.taoensso/nippy "1.2.1"]        ; Stable
-[com.taoensso/nippy "2.0.0-alpha8"] ; Development (notes below)
+[com.taoensso/nippy "2.0.0-alpha9"] ; Development (notes below)
 ```
 
-2.x adds pluggable compression, crypto support (also pluggable), an improved API (including much better error messages), and hugely improved performance. It **is backwards compatible**, but please note that the old `freeze-to-bytes`/`thaw-from-bytes` API has been **deprecated** in favor of `freeze`/`thaw`. **PLEASE REPORT ANY PROBLEMS!**
+v2 adds pluggable compression, crypto support (also pluggable), an improved API (including much better error messages), easier integration into other tools/libraries, and hugely improved performance. It **is backwards compatible**, but please note that the old `freeze-to-bytes`/`thaw-from-bytes` API has been **deprecated** in favor of `freeze`/`thaw`. **PLEASE REPORT ANY PROBLEMS!**
 
 # Nippy, a Clojure serialization library
 
@@ -20,7 +20,8 @@ Nippy is an attempt to provide a reliable, high-performance **drop-in alternativ
   * **Reader-fallback** for difficult/future types (including Clojure 1.4+ tagged literals).
   * **Full test coverage** for every supported type.
   * Fully pluggable **compression**, including built-in high-performance [Snappy](http://code.google.com/p/snappy/) compressor.
-  * Fully pluggable **encryption**, including built-in high-strength AES128 enabled with a single `:password [:salted "my-password"]` option. (2.0.0+)
+  * Fully pluggable **encryption**, including built-in high-strength AES128 enabled with a single `:password [:salted "my-password"]` option. (v2+)
+  * Utils for **easy integration into 3rd-party tools/libraries**. (v2+)
 
 ## Getting started
 
@@ -103,7 +104,7 @@ Couldn't be simpler!
 
 ### Encryption (currently in **ALPHA**)
 
-As of 2.0.0, Nippy also gives you **dead simple data encryption**. Add a single option to your usual freeze/thaw calls like so:
+Nippy v2+ also gives you **dead simple data encryption**. Add a single option to your usual freeze/thaw calls like so:
 
 ```clojure
 (nippy/freeze nippy/stress-data {:password [:salted "my-password"]}) ; Encrypt

project.clj

@@ -1,4 +1,4 @@
-(defproject com.taoensso/nippy "2.0.0-alpha8"
+(defproject com.taoensso/nippy "2.0.0-alpha9"
   :description "Clojure serialization library"
   :url "https://github.com/ptaoussanis/nippy"
   :license {:name "Eclipse Public License"

src/clj/taoensso/nippy.clj

@@ -269,7 +269,8 @@
   [^bytes ba & [{:keys [read-eval? password compressor encryptor legacy-opts]
                  :or   {legacy-opts {:compressed? true}
                         compressor  snappy-compressor
-                        encryptor   aes128-encryptor}}]]
+                        encryptor   aes128-encryptor}
+                 :as   opts}]]
 
   (let [ex (fn [msg & [e]] (throw (Exception. (str "Thaw failed: " msg) e)))
         try-thaw-data
@@ -301,7 +302,8 @@
        (and compressed? (not compressor))
        (ex "Compressed data. Try again with compressor.")
        (and encrypted? (not password))
-       (ex "Encrypted data. Try again with password.")
+       (if (::tools-thaw? opts) ::need-password
+           (ex "Encrypted data. Try again with password."))
        :else (try (try-thaw-data data-ba head-meta)
                   (catch Exception _ (try-thaw-data ba nil))))
 

src/clj/taoensso/nippy/tools.clj

@@ -0,0 +1,46 @@
+(ns taoensso.nippy.tools
+  "Alpha - subject to change.
+  Utilities for third-party tools that want to add fully-user-configurable Nippy
+  support. Used by Carmine and Faraday."
+  {:author "Peter Taoussanis"}
+  (:require [taoensso.nippy       :as nippy]
+            [taoensso.nippy.utils :as utils]))
+
+(defrecord WrappedForFreezing [value opts])
+(defn wrapped-for-freezing? [x] (instance? WrappedForFreezing x))
+(defn wrap-for-freezing
+  "Wraps arg (any freezable data type) so that (tools/freeze <wrapped-arg>)
+  will freeze the arg using given options."
+  [value & [opts]] (WrappedForFreezing. value opts))
+
+(defn freeze
+  "Like `nippy/freeze` but takes options from special argument wrapper when
+  present."
+  [x & [{:keys [default-opts]}]]
+  (if (wrapped-for-freezing? x)
+    (nippy/freeze (:value x) (or (:opts x) default-opts))
+    (nippy/freeze x default-opts)))
+
+(comment (freeze (wrap-for-freezing "wrapped"))
+         (freeze "unwrapped"))
+
+(defrecord EncryptedFrozen [ba])
+(defn encrypted-frozen? [x] (instance? EncryptedFrozen x))
+
+(def ^:dynamic *thaw-opts* nil)
+(defmacro with-thaw-opts [opts & body] `(binding [*thaw-opts* ~opts] ~@body))
+
+(defn thaw
+  "Like `nippy/thaw` but takes options from *thaw-opts* binding, and wraps
+  encrypted bytes for easy identification when no password has been provided
+  for decryption."
+  [ba & {:keys [default-opts]}]
+  (let [result (nippy/thaw ba (merge (or *thaw-opts* default-opts)
+                                     {:taoensso.nippy/tools-thaw? true}))]
+    (if (= result :taoensso.nippy/need-password)
+      (EncryptedFrozen. ba)
+      result)))
+
+(comment (thaw (nippy/freeze "c" {:password [:cached "p"]}))
+         (with-thaw-opts {:password [:cached "p"]}
+           (thaw (nippy/freeze "c" {:password [:cached "p"]}))))