New dht example for values storages

dht-for-values-storage/README.md

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+# p2p Chat and storing values [using PubSub and DHT]
+This programs demonstrates the use of a pubsub pattern to broadcast values in the network. Get them stored into some peer (not always the one adding them) and being able to retrieve them from any node by having the CID of the value wanted.
+
+This example is based on the **ipfs-camp-2019 pubsub code**.
+
+## How to build
+ > go get -v -d ./...
+
+ > go build .
+
+ # Code explanation
+ The functions added to the **ipfs-camp-2019** last code behave in the following way:
+
+
+- /get cid:
+    - getProviderrInfo (dht, ctx, cid)  peer.AddrInfo
+    - getValue (dht, ctx, "cid:addr") : 
+        - getProviderInfo 
+        - Connect To it 
+        - GetWriter 
+
+- /put value: 
+    - addValue(dht, ctx, value)
+        - FindClosestPeerInfo(dht, ctx, cid) peer.AddrInfo
+        - pushValue (dht, ctx, cid, value) :
+            - FindClosestPeer 
+            - Connect to it 
+            - PutWriter 
+
+- Handle Stream:
+    - Reading/Writing into the stream
+        - ReadData(stream) :
+            - If it is “cid:value”:
+                - pushToStore(cid:value)
+                - provide it to the network
+            - If it is “get:cid:addr”:
+                - getReader(stream,cid+addr)
+            - If it is “value”
+                - PrintItToScreen
+        - WriteData(stream, valueToBeWritten) 
+
+- Put Writer:
+    - WriteData(stream, cid:value)
+- Get Writer:
+    - Writedata(stream, get:cid:addr)
+- Get Reader: 
+    - getValueFromStore(cid) string
+    - WriteData(stream, value) 
+
+# How it works
+  > ./dht-for-values-storage -h 
+
+```
+  This programs demonstrates the use of a pubsub pattern to broadcast values in the network. 
+  Get them stored into some peer (not always the one adding them) and being able to retrieve them from any 
+  node that have the CID of the value wanted.
+
+Usage: Run './start
+  -h	Display Help
+  -host string
+    	The bootstrap node host listen address
+    	 (default "0.0.0.0")
+  -pid string
+    	Sets a protocol id for stream headers (default "/chat/1.1.0")
+  -port int
+    	node listen port (default 4001)
+  -topic string
+    	Unique string to identify group of nodes (default "/libp2p/example/chat/1.0.0")
+```
+
+#### Author
+CHAMI Rachid