support preput,predel,prebatch

Author: mafintosh

README.md

@@ -93,7 +93,10 @@ Returns a new duplex server stream that you should connect with a client. Option
 
 ``` js
 {
-  readonly: true // make the database be accessible as read only
+  readonly: true, // make the database be accessible as read only
+  preput: function (key, val, cb) {}, // called before puts
+  predel: function (key, cb) {}, // called before dels
+  prebatch: function (batch, cb) {} // called before batches
 }
 ```
 

server.js

@@ -12,11 +12,17 @@ var DECODERS = [
 ]
 
 module.exports = function (db, opts) {
-  var readonly = !!(opts && opts.readonly)
+  if (!opts) opts = {}
+
+  var readonly = !!(opts.readonly)
   var decode = lpstream.decode()
   var encode = lpstream.encode()
   var stream = duplexify(decode, encode)
 
+  var preput = opts.preput || function (key, val, cb) { cb(null) }
+  var predel = opts.predel || function (key, cb) { cb(null) }
+  var prebatch = opts.prebatch || function (ops, cb) { cb(null) }
+
   if (db.isOpen()) ready()
   else db.open(ready)
 
@@ -73,8 +79,11 @@ module.exports = function (db, opts) {
     }
 
     function onput (req) {
-      down.put(req.key, req.value, function (err) {
-        callback(req.id, err, null)
+      preput(req.key, req.value, function (err) {
+        if (err) return callback(err)
+        down.put(req.key, req.value, function (err) {
+          callback(req.id, err, null)
+        })
       })
     }
 
@@ -85,8 +94,11 @@ module.exports = function (db, opts) {
     }
 
     function ondel (req) {
-      down.del(req.key, function (err) {
-        callback(req.id, err)
+      predel(req.key, function (err) {
+        if (err) return callback(err)
+        down.del(req.key, function (err) {
+          callback(req.id, err)
+        })
       })
     }
 
@@ -95,8 +107,11 @@ module.exports = function (db, opts) {
     }
 
     function onbatch (req) {
-      down.batch(req.ops, function (err) {
-        callback(req.id, err)
+      prebatch(req.ops, function (err) {
+        if (err) return callback(err)
+        down.batch(req.ops, function (err) {
+          callback(req.id, err)
+        })
       })
     }
 
@@ -122,6 +137,13 @@ function Iterator (down, req, encode) {
 
   this.batch = req.batch || 0
 
+  if (req.options) {
+    if (req.options.gt === null) req.options.gt = undefined
+    if (req.options.gte === null) req.options.gte = undefined
+    if (req.options.lt === null) req.options.lt = undefined
+    if (req.options.lte === null) req.options.lte = undefined
+  }
+
   this._iterator = down.iterator(req.options)
   this._encode = encode
   this._send = send

test/basic.js

@@ -5,7 +5,7 @@ var levelup = require('levelup')
 var multileveldown = require('../')
 
 tape('get', function (t) {
-  var db = levelup('no-location', {db: memdown})
+  var db = levelup('no-location', {db: mem})
   var stream = multileveldown.server(db)
   var client = multileveldown.client()
 
@@ -21,7 +21,7 @@ tape('get', function (t) {
 })
 
 tape('put', function (t) {
-  var db = levelup('no-location', {db: memdown})
+  var db = levelup('no-location', {db: mem})
   var stream = multileveldown.server(db)
   var client = multileveldown.client()
 
@@ -38,7 +38,7 @@ tape('put', function (t) {
 })
 
 tape('readonly', function (t) {
-  var db = levelup('no-location', {db: memdown})
+  var db = levelup('no-location', {db: mem})
 
   db.put('hello', 'verden')
 
@@ -58,7 +58,7 @@ tape('readonly', function (t) {
 })
 
 tape('del', function (t) {
-  var db = levelup('no-location', {db: memdown})
+  var db = levelup('no-location', {db: mem})
   var stream = multileveldown.server(db)
   var client = multileveldown.client()
 
@@ -78,7 +78,7 @@ tape('del', function (t) {
 })
 
 tape('batch', function (t) {
-  var db = levelup('no-location', {db: memdown})
+  var db = levelup('no-location', {db: mem})
   var stream = multileveldown.server(db)
   var client = multileveldown.client()
 
@@ -99,7 +99,7 @@ tape('batch', function (t) {
 })
 
 tape('read stream', function (t) {
-  var db = levelup('no-location', {db: memdown})
+  var db = levelup('no-location', {db: mem})
   var stream = multileveldown.server(db)
   var client = multileveldown.client()
 
@@ -118,7 +118,7 @@ tape('read stream', function (t) {
 })
 
 tape('read stream (gt)', function (t) {
-  var db = levelup('no-location', {db: memdown})
+  var db = levelup('no-location', {db: mem})
   var stream = multileveldown.server(db)
   var client = multileveldown.client()
 
@@ -134,3 +134,7 @@ tape('read stream (gt)', function (t) {
     }))
   })
 })
+
+function mem () {
+  return memdown()
+}