Extract String with regex

Question

In Node.js, I would like to extract multiple strings from a given string. The string to search from looks like this:

Mon May 17 10:17:44 2021 SEND MESSAGE TO NETWORK (10.0.158.24:5060 [UDP]) (BUFF LEN = 308)
----------------------utf8-----------------------
SIP/2.0 100 Trying
To: "+3212345678" <sip:[email protected];user=phone>
From: "+32456123456" <sip:[email protected];user=phone>;tag=1c506737759
Call-ID: [email protected]
CSeq: 1 INVITE
Via: SIP/2.0/UDP 10.0.158.24:5060;branch=z9hG4bKac551823835
Content-Length: 0

-------------------------------------------------
Mon May 17 10:17:44 2021 11f7 [CCall::checkAuthentication] INVITE
Mon May 17 10:17:44 2021 [DBG: CResponse::freeAttributes] Ends
Mon May 17 10:17:44 2021 6367C [CMessage::send] sip_sendMessage (10.0.158.24:5060)
Mon May 17 10:17:44 2021 SEND MESSAGE TO NETWORK (10.0.158.24:5060 [UDP]) (BUFF LEN = 496)
----------------------utf8-----------------------
SIP/2.0 480 Temporarily not available
Allow: INVITE, ACK, CANCEL, BYE, PRACK, NOTIFY, REFER, SUBSCRIBE, OPTIONS, UPDATE
User-Agent: OmniPCX Enterprise R12.4 m5.204.2.b
To: "+3212345678" <sip:[email protected];user=phone>;tag=fa4096f6eb58184a573b7fcb86a7adff
From: "+32456123456" <sip:[email protected];user=phone>;tag=1c506737759
Call-ID: [email protected]
CSeq: 1 INVITE
Via: SIP/2.0/UDP 10.0.158.24:5060;branch=z9hG4bKac551823835
Content-Length: 0

-------------------------------------------------
1621239464 -> Mon May 17 10:17:44 2021 6367C [CMessage::onSendSuccess]
Mon May 17 10:17:44 2021 2107 [CTransaction::onSendSuccess] CMessage 6367C send Success
Mon May 17 10:17:44 2021 15cd [CDialog::onSendSuccess]

I want to extract everything between '----------------------utf8-----------------------' and '-------------------------------------------------'

I tried following:

let matches = givenString.match(/-{22}utf8-{23}(.*?)-{49}/g).map((val) => {
    return val.replace(/-{22}utf8-{23}/g, '')
})
console.log(matches)

But the result is 'TypeError: Cannot read property 'map' of null'

I also tried to without counting the '-' characters

let matches = givenString.match(/----------------------utf8-----------------------(.*?)-------------------------------------------------/g)

But same result ('TypeError: Cannot read property 'map' of null')

I think you should add s flag at the end, single line. With it . matches new line characters. — Egan Wolf
– Egan Wolf, Commented May 18, 2021 at 13:36
Maybe the problem lies where you read the text into givenString? — Detonar
– Detonar, Commented May 18, 2021 at 13:41
I'm creating the String by reading a file let givenString = fs.readFileSync('test2.txt').toString(), could this be the problem ? — sdeferme
– sdeferme, Commented May 18, 2021 at 13:52

yunzen · Accepted Answer · 2021-05-18 14:04:01Z

The Regexp doesn't work that way. It will not recognize the (.*?) part as to be accross multiple lines. For this you have to be using the s flag.

let matches = givenString.match(/-{22}utf8-{23}(.*?)-{49}/gs) //...
-----------------------------------------------------------^

let givenString = `Mon May 17 10:17:44 2021 SEND MESSAGE TO NETWORK (10.0.158.24:5060 [UDP]) (BUFF LEN = 308)
----------------------utf8-----------------------
SIP/2.0 100 Trying
To: "+3212345678" <sip:[email protected];user=phone>
From: "+32456123456" <sip:[email protected];user=phone>;tag=1c506737759
Call-ID: [email protected]
CSeq: 1 INVITE
Via: SIP/2.0/UDP 10.0.158.24:5060;branch=z9hG4bKac551823835
Content-Length: 0

-------------------------------------------------
Mon May 17 10:17:44 2021 11f7 [CCall::checkAuthentication] INVITE
Mon May 17 10:17:44 2021 [DBG: CResponse::freeAttributes] Ends
Mon May 17 10:17:44 2021 6367C [CMessage::send] sip_sendMessage (10.0.158.24:5060)
Mon May 17 10:17:44 2021 SEND MESSAGE TO NETWORK (10.0.158.24:5060 [UDP]) (BUFF LEN = 496)
----------------------utf8-----------------------
SIP/2.0 480 Temporarily not available
Allow: INVITE, ACK, CANCEL, BYE, PRACK, NOTIFY, REFER, SUBSCRIBE, OPTIONS, UPDATE
User-Agent: OmniPCX Enterprise R12.4 m5.204.2.b
To: "+3212345678" <sip:[email protected];user=phone>;tag=fa4096f6eb58184a573b7fcb86a7adff
From: "+32456123456" <sip:[email protected];user=phone>;tag=1c506737759
Call-ID: [email protected]
CSeq: 1 INVITE
Via: SIP/2.0/UDP 10.0.158.24:5060;branch=z9hG4bKac551823835
Content-Length: 0

-------------------------------------------------
1621239464 -> Mon May 17 10:17:44 2021 6367C [CMessage::onSendSuccess]
Mon May 17 10:17:44 2021 2107 [CTransaction::onSendSuccess] CMessage 6367C send Success
Mon May 17 10:17:44 2021 15cd [CDialog::onSendSuccess]
`

let matches = givenString.match(/-{22}utf8-{23}(.*?)-{49}/gs).map((val) => {
    return val.replace(/-{22}utf8-{23}/g, '')
})
console.log(matches)

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