Merge pull request #4398 from eviltofu/#4168_Add_documentation_to_describe_how_chains.zip_is_created_and_what_it_is_used_for

Added documentation and a target to Makefile to download, compress, and add the chains.zip file to the AlphaWallet project.

Makefile

@@ -4,6 +4,8 @@ gem_cmd = gem
 bundle_gem = "bundler:2.2.33"
 vendor_path = ./vendor/bundle
 beautify_cmd = ./Pods/xcbeautify/xcbeautify
+curl_cmd = /usr/bin/curl
+compress_cmd = ./scripts/compress_chains
 
 all: target
 	@echo "Please specify a target. Please use 'make target' to show targets."
@@ -18,7 +20,8 @@ target:
 	@echo "test14             : run tests for iOS 14.5."
 	@echo "test15             : run tests for iOS 15.2."
 	@echo "test               : run the tests for latest iOS (15.2)."
-	@echo "clean         : Remove all the pods and gems."
+	@echo "clean              : remove all the pods and gems."
+	@echo "update_chains_file : update the chains.zip file in the project."
 
 check_brew:
 	@$(brew_cmd) --version 1>/dev/null 2>/dev/null; \
@@ -103,3 +106,16 @@ build_and_run_booted:
 	@xcrun simctl install booted ./build/Build/Products/Debug-iphonesimulator/AlphaWallet.app
 	@xcrun simctl launch booted com.stormbird.alphawallet
 
+update_chains_file:
+	@echo "Deleting chains file in scripts folder."
+	@rm -f ./scripts/chains.json
+	@rm -f ./scripts/chains.json.zip
+	@echo "Downloading chains file."
+	@$(curl_cmd) --output ./scripts/chains.json https://chainid.network/chains.json
+	@echo "Compressing."
+	@$(compress_cmd)
+	@echo "Moving compressed file into project."
+	@mv scripts/chains.json.zip AlphaWallet/Rpc\ Network/chains.zip
+	@rm -f ./scripts/chains.json
+	@echo "Update completed."
+

docs/data-source-chains.md

@@ -0,0 +1,22 @@
+The chains.json file is downloaded from https://chainid.network/chains.json.
+
+This file is then compressed using NSData.CompressionAlgorithm.lzma and stored raw without any headers.
+
+It is then renamed as chains.zip and must be added to the Rpc Network group of the project.
+
+A Makefile target has been added to automate this process. At the command line, type in:
+
+```
+make update_chains_file
+```
+
+and you should see the following response:
+
+```console
+Deleting chains file in scripts folder.
+Downloading chains file.
+################################################################################################################# 100.0%
+Compressing.
+Moving compressed file into project.
+Update completed.
+```

scripts/compress_chains

@@ -0,0 +1,24 @@
+#!/usr/bin/env swift
+
+import Foundation
+
+let selectedCompressionAlgorithm = NSData.CompressionAlgorithm.lzma
+
+func compressChainFile(inputFileName: String, outputFileName: String) throws {
+    let inputFileHandle = FileHandle(forReadingAtPath: inputFileName)!
+    let inputData = inputFileHandle.readDataToEndOfFile() as NSData
+    let outputData = try inputData.compressed(using: selectedCompressionAlgorithm) as Data
+    FileManager.default.createFile(atPath: outputFileName, contents: outputData, attributes: nil)
+    try inputFileHandle.close()
+}
+
+do {
+    try compressChainFile(inputFileName: "scripts/chains.json", outputFileName: "scripts/chains.json.zip")
+    exit(0)
+} catch {
+    print("An error occurred: \(error)")
+    exit(-1)
+}
+
+
+