Disclaimer: This software is only at proof-of-concept stage, don't pretend this software to be ready for production usage. It works on the designed path, but it needs a lot more development. You have been warned !
DocsChain is a private blockchain to store and certify documents, designed to be very easy to use and deploy. You can create small peer-to-peer networks of documents contributors. It doesn't have a mining algorithm and so it cannot be used in a public network. However it implements the basic features of a working blockchain. The chain is stored as a serialised .dc file in the Config Directory along with another file, with network peers. The chain doesn't include uploaded documents. Documents are stored into the FileStorage Directory using the block Guid. It is primarly done for PDF storing, but it can work with other extensions (doc,docx,txt,xls,xlsx,png,jpg,jpeg,gif,csv)
Code is based on Asp .Net core 2.0 + c# + WebApi Controllers\WebAppController.cs is for the GUI Action methods Controllers\ChainController.cs is used by WebApis controller, for the intra-nodes communication.
Only the GUI has dependency with Bootstrap, Jquery, and for PDF viewing, the great plugin iziModal by Marcelo Dolce .
I read an article on Medium.com by Lauri Hartikka, explaining how to build a basic blockchain in Javascript without all the hassles of blockchain players. I thought it was the time to create my own implementation. Thanks Lauri for the great article ! Here are some Highlights from his article:
The basic concept of blockchain is quite simple: a distributed database that maintains a continuously growing list of ordered records.
When you first run a DocsChain node, it will check locally for Config folder and FileStorage folder. If missing, they will be created, along with an empty chain. GUI has no authentication, you can interact immediately with the node (ARGH :-) ). The GUI is absolutely basic, built with Bootstrap 4.
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Documents Blocks
Here you can preview (only PDF) and download documents in the blockchain. You'll see immediately only the Genesis Block, built during node bootstrap. Moreover, you can upload a pdf documents and add it to the chain. If you have built and connected more nodes, the documents will be broadcasted to the other peers. Imagine to have 3 offices in your Intranet, and you want the to "certify" a document (data and upload timing). Every node can contribute to the Chain, adding any new documents when required. DocsChain limit is now that, without login, I cannot write to the chain who uploaded a document.
- Node Status
Here you can find when the DocsChain has been created the first time (Genesis Date) You can see the list of Peers connected.
- Node Status
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System Functions
In this area you can perform three actions
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if you want to Connect and Sync to another DocsChain Node. Just enter another node IP:PORT (ex: 192.168.1.50:5979) and push the "Bootstrap Node" button. You'll see in the logs the chain Sync and network nodes addresses exchange. I tested DocsChain with 4 working nodes.
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Pressing Add Test Docs will add 3 sample PDFs to the chain without needing you to upload them manually.
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Delete the core chain and documents. But it will not delete the network peers list (got to develop it).
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Download the project and just Run it with Visual Studio 2017. If everything works fine, you'll have a consolle opening with logs and the browser will open on the Chain Node Url . If browser is not opening , go to the url http://[YourNodeIP]:[YourNodePort] If you want customize Node Name, Listening IP or Port, edit appsettings.json file:
"NodeIdentification": {
"Name": "Node 10",
"ListeningPort": "5979",
"IPEndpoint": "http://192.168.1.147:5979"
}
Keep ListeningPort and the IPEndpoint port the same (this is a POC, it'll be optimized later...) It is mandatory to use the real IP of Network Interface (ipconfig /all on command line) if you want to make the POC work in your intranet on different machines. You cannot use localhost or 127.0.0.1 here. You can do it (not tested) only if you're going to run multiple DocsChain nodes on the same machine .
If you are a brave and you want to showcase DocsChain with multiple nodes (on the same machine, never tried on different machines), I suggest the following approach (remember to replace the IP below with your own IP and desired port):
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Right Click on Project Root Node and Publish to a Folder. (es:c:\DocsChainBase)
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Clone the Folder as c:\DocsChain5010
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Clone the Folder as c:\DocsChain5020
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Open c:\DocsChain5010\appsettings.json and set
"NodeIdentification": { "Name": "Node 5010", "ListeningPort": "5010", "IPEndpoint": "http://192.168.1.147:5010" }
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Open c:\DocsChain5020\appsettings.json and set
"NodeIdentification": { "Name": "Node 5020", "ListeningPort": "5020", "IPEndpoint": "http://192.168.1.147:5020" }
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Now you have 2 configured nodes .
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Open a Command Line 1 and cd \DocsChain5010\
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launch the first node with:
dotnet DocsChain.dll -
Open the browser and go to http://192.168.1.147:5010/ (Rememeber this is my example IP, use yours !!)
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Add some documents or use the System Menù to add them to the chain (5010)
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Go to \DocsChain5020\
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run
dotnet DocsChain.dll.The second node will boot -
Browse to http://localhost:5020/
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Go to the System menu
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Enter the First Node Boot Url without http (es: 192.168.1.147:5010)
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If everything has gone fine, you have 2 synced DocsChain nodes .
You can repeat with other nodes and boot from any network connected live node.
Now you can try to upload a document on any node, and it will be broadcasted to the others in the network. POC End :-)
How to restart from the beginning when you are going crazy:
- stop a node
- delete Config Folder and FileStorage Folder
- restart the node
- User Authentication and user management.
- Packaging the app as a Windows Service
- Secure data transfer between nodes with HTTPS.
- Docs Encription on file system.
- File watcher to keep an eye on documents stored on local filesystem.
- Auto-Recover documents from other nodes if found a file corrupted (different Hash)
- General recovery of BlockChain if something is going wrong
- Supporting more native files viewer in the GUI
- Search along documents feature
- ...
"Hidden" Command line switches...
dotnet DocsChain.dll --boot http://localhost:5030 (To boot a node without using the GUI)
dotnet DocsChain.dll --create-test-chain true (boot and add immediately sample documents to the chain)
Really, this is my first open source projects. I don't know if it will catch someone interest, and I never contributed to others projects. If you find it interesting and want to contribute, drop me a line. Thanks A POC by Giulio Fronterotta
This project is licensed under the terms of the MIT license.