feat: add chainId (network) as url parameter (#3057)

* read from query param and change networks if necessary

* dont open network selector menu on url param change

* prompt network change when url changes

* keep url, network in sync

* use chain name instead of id in url param

* only prompt network switch if url chain doesnt match

src/components/Header/NetworkSelector.tsx

 import { Trans } from '@lingui/macro'
 import { CHAIN_INFO } from 'constants/chainInfo'
-import { SupportedChainId } from 'constants/chains'
+import { CHAIN_IDS_TO_NAMES, SupportedChainId } from 'constants/chains'
 import useActiveWeb3React from 'hooks/useActiveWeb3React'
 import { useOnClickOutside } from 'hooks/useOnClickOutside'
-import { useCallback, useRef } from 'react'
+import useParsedQueryString from 'hooks/useParsedQueryString'
+import usePrevious from 'hooks/usePrevious'
+import { ParsedQs } from 'qs'
+import { useCallback, useEffect, useRef } from 'react'
 import { ArrowDownCircle, ChevronDown } from 'react-feather'
+import { useHistory } from 'react-router-dom'
 import { useModalOpen, useToggleModal } from 'state/application/hooks'
 import { addPopup, ApplicationModal } from 'state/application/reducer'
 import styled from 'styled-components/macro'
 import { ExternalLink, MEDIA_WIDTHS } from 'theme'
+import { replaceURLParam } from 'utils/routes'
 
 import { useAppDispatch } from '../../state/hooks'
 import { switchToNetwork } from '../../utils/switchToNetwork'
@@ -211,31 +216,88 @@ function Row({
   return rowContent
 }
 
+const getParsedChainId = (parsedQs?: ParsedQs) => {
+  const chain = parsedQs?.chain
+  if (!chain || typeof chain !== 'string') return { urlChain: undefined, urlChainId: undefined }
+
+  return { urlChain: chain.toLowerCase(), urlChainId: getChainIdFromName(chain) }
+}
+
+const getChainIdFromName = (name: string) => {
+  const entry = Object.entries(CHAIN_IDS_TO_NAMES).find(([_, n]) => n === name)
+  const chainId = entry?.[0]
+  return chainId ? parseInt(chainId) : undefined
+}
+
+const getChainNameFromId = (id: string | number) => {
+  // casting here may not be right but fine to return undefined if it's not a supported chain ID
+  return CHAIN_IDS_TO_NAMES[id as SupportedChainId] || ''
+}
+
 export default function NetworkSelector() {
   const { chainId, library } = useActiveWeb3React()
+  const parsedQs = useParsedQueryString()
+  const { urlChain, urlChainId } = getParsedChainId(parsedQs)
+  const prevChainId = usePrevious(chainId)
   const node = useRef<HTMLDivElement>()
   const open = useModalOpen(ApplicationModal.NETWORK_SELECTOR)
   const toggle = useToggleModal(ApplicationModal.NETWORK_SELECTOR)
   useOnClickOutside(node, open ? toggle : undefined)
 
+  const history = useHistory()
+
   const info = chainId ? CHAIN_INFO[chainId] : undefined
 
   const dispatch = useAppDispatch()
 
-  const handleRowClick = useCallback(
-    (targetChain: number) => {
+  const handleChainSwitch = useCallback(
+    (targetChain: number, skipToggle?: boolean) => {
       if (!library) return
       switchToNetwork({ library, chainId: targetChain })
-        .then(() => toggle())
+        .then(() => {
+          if (!skipToggle) {
+            toggle()
+          }
+          history.replace({
+            search: replaceURLParam(history.location.search, 'chain', getChainNameFromId(targetChain)),
+          })
+        })
         .catch((error) => {
           console.error('Failed to switch networks', error)
-          toggle()
+
+          // we want app network <-> chainId param to be in sync, so if user changes the network by changing the URL
+          // but the request fails, revert the URL back to current chainId
+          if (chainId) {
+            history.replace({ search: replaceURLParam(history.location.search, 'chain', getChainNameFromId(chainId)) })
+          }
+
+          if (!skipToggle) {
+            toggle()
+          }
+
           dispatch(addPopup({ content: { failedSwitchNetwork: targetChain }, key: `failed-network-switch` }))
         })
     },
-    [dispatch, library, toggle]
+    [dispatch, library, toggle, history, chainId]
   )
 
+  useEffect(() => {
+    // when network change originates from wallet or dropdown selector, just update URL
+    if (chainId && chainId !== prevChainId) {
+      history.replace({ search: replaceURLParam(history.location.search, 'chain', getChainNameFromId(chainId)) })
+      // otherwise assume network change originates from URL
+    } else if (urlChainId && urlChainId !== chainId) {
+      handleChainSwitch(urlChainId, true)
+    }
+  }, [chainId, urlChainId, prevChainId, handleChainSwitch, history])
+
+  // set chain parameter on initial load if not there
+  useEffect(() => {
+    if (chainId && !urlChainId) {
+      history.replace({ search: replaceURLParam(history.location.search, 'chain', getChainNameFromId(chainId)) })
+    }
+  }, [chainId, history, urlChainId, urlChain])
+
   if (!chainId || !info || !library) {
     return null
   }
@@ -252,10 +314,10 @@ export default function NetworkSelector() {
           <FlyoutHeader>
             <Trans>Select a network</Trans>
           </FlyoutHeader>
-          <Row onSelectChain={handleRowClick} targetChain={SupportedChainId.MAINNET} />
-          <Row onSelectChain={handleRowClick} targetChain={SupportedChainId.POLYGON} />
-          <Row onSelectChain={handleRowClick} targetChain={SupportedChainId.OPTIMISM} />
-          <Row onSelectChain={handleRowClick} targetChain={SupportedChainId.ARBITRUM_ONE} />
+          <Row onSelectChain={handleChainSwitch} targetChain={SupportedChainId.MAINNET} />
+          <Row onSelectChain={handleChainSwitch} targetChain={SupportedChainId.POLYGON} />
+          <Row onSelectChain={handleChainSwitch} targetChain={SupportedChainId.OPTIMISM} />
+          <Row onSelectChain={handleChainSwitch} targetChain={SupportedChainId.ARBITRUM_ONE} />
         </FlyoutMenu>
       )}
     </SelectorWrapper>

src/constants/chains.ts

@@ -18,6 +18,20 @@ export enum SupportedChainId {
   POLYGON_MUMBAI = 80001,
 }
 
+export const CHAIN_IDS_TO_NAMES = {
+  [SupportedChainId.MAINNET]: 'mainnet',
+  [SupportedChainId.ROPSTEN]: 'ropsten',
+  [SupportedChainId.RINKEBY]: 'rinkeby',
+  [SupportedChainId.GOERLI]: 'goerli',
+  [SupportedChainId.KOVAN]: 'kovan',
+  [SupportedChainId.POLYGON]: 'polygon',
+  [SupportedChainId.POLYGON_MUMBAI]: 'polygon_mumbai',
+  [SupportedChainId.ARBITRUM_ONE]: 'arbitrum',
+  [SupportedChainId.ARBITRUM_RINKEBY]: 'arbitrum_rinkeby',
+  [SupportedChainId.OPTIMISM]: 'optimism',
+  [SupportedChainId.OPTIMISTIC_KOVAN]: 'optimistic_kovan',
+}
+
 /**
  * Array of all the supported chain IDs
  */

src/utils/routes.ts

+export const replaceURLParam = (search: string, param: string, newValue: string) => {
+  const searchParams = new URLSearchParams(search)
+  searchParams.set(param, newValue)
+  return searchParams.toString()
+}