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Posted to users@groovy.apache.org by Gerald Wiltse <je...@gmail.com> on 2016/03/04 15:18:12 UTC
Groovy Hash Calculations
Hello All,
I have this block, it's pretty compressed, just wondering if there is a
more groovy way to handle reading the buffer and computing the hash.
def messageDigest = MessageDigest.getInstance("SHA1")
def dis = new DigestInputStream(content, messageDigest)
byte[] buffer = new byte[1024];
while (dis.read(buffer) != -1) {}
def sha1Hex = new BigInteger(1,
messageDigest.digest()).toString(16).padLeft(40, '0')
Gerald R. Wiltse
jerrywiltse@gmail.com
Re: Groovy Hash Calculations
Posted by Gerald Wiltse <je...@gmail.com>.
I fixed the exception, had to swap the dis = and digest = lines around.
Now just looking for help making this more elegant and groovy.
Gerald R. Wiltse
jerrywiltse@gmail.com
On Wed, Mar 9, 2016 at 12:37 PM, Gerald Wiltse <je...@gmail.com>
wrote:
> Ok, returning back to this, my test case did not want to save the file,
> only calculate the hash as memory-efficiently as possible without
> buffereing. Mission accomplished.
>
> However now my real implementation does want to save and hash, again as
> memory-efficiently as possible.
>
> This is what I've created so far.
>
> First, getting error at the "while()" loop:
>
> Caught: java.lang.NullPointerException
> java.lang.NullPointerException
> at java_io_FilterInputStream$read.call(Unknown Source)
>
>
> Second, I'm really unsatisfied with it.
> 1. Declaring all the variables before the loop is... really verbose
> 2. It seems like the hash and file write operations should be separated.
>
>
> Does anyone have any suggestions?
>
> def baseDir = new File("c:/data")
> File localFile
> byte[] buffer
> DigestInputStream dis
> MessageDigest digest
> ByteArrayInputStream bais
> jarList.each{Map jarMetadata ->
> content.filePath = jarMetadata['path']
> bais = content.downloadContent(true, [bt_package: testPkg])
> localFile = new File(baseDir, jarMetadata['path'])
> localFile.parentFile.mkdirs()
> localFile.withOutputStream {fos->
> buffer = new byte[1024]
> dis = new DigestInputStream(bais, digest)
> digest = MessageDigest.getInstance("SHA1")
> while (dis.read(buffer) != -1) {
> fos.write(buffer)
> }
> }
> assert digest.digest().encodeHex() == jarMetadata['sha1']
> }
>
>
> Gerald R. Wiltse
> jerrywiltse@gmail.com
>
>
> On Fri, Mar 4, 2016 at 11:30 AM, Winnebeck, Jason <
> Jason.Winnebeck@windstream.com> wrote:
>
>> Only the “short” solution I wrote involved buffering to memory. The
>> “long” solution I wrote involves no buffering. The DigestInputStream is not
>> related to whether or not there is buffering, all it does is it lets you
>> read the stream and get a digest at the same time. If you are just throwing
>> out the data, there’s no need for the DigestInputStream. DigestInputStream
>> just takes the result of every read call and sends the bytes to
>> MessageDigest#update before returning the data. DigestInputStream makes
>> sense if you were, for example, passing that input stream to another method
>> that wrote the content to a file then you wanted to get the digest after
>> the file write was complete.
>>
>>
>>
>> Jason
>>
>>
>>
>> *From:* Gerald Wiltse [mailto:jerrywiltse@gmail.com]
>> *Sent:* Friday, March 04, 2016 10:08 AM
>> *To:* users@groovy.apache.org
>> *Subject:* Re: Groovy Hash Calculations
>>
>>
>>
>> I'm trying to verify the sha1 hash on a file download without saving it
>> to disk, and without buffering the whole thing. I think this solution
>> might buffer all the data into "content" before going into the eachByte
>> loop. I thought that was the reason for the DigestInputStream. Do you know
>> if this is correct?
>>
>>
>> Gerald R. Wiltse
>> jerrywiltse@gmail.com
>>
>>
>>
>>
>>
>> On Fri, Mar 4, 2016 at 9:40 AM, Winnebeck, Jason <
>> Jason.Winnebeck@windstream.com> wrote:
>>
>> Here is how I would do it. I provide both a “short” solution and a “long”
>> one. I would use the “short” solution if I was making for example a
>> developer only tool and I knew I was only hashing small things for example
>> a configuration file in a build script and want a one-liner. Otherwise I’d
>> use the “long” version.
>>
>>
>>
>> //If the content is guaranteed to be short:
>>
>> def content = new ByteArrayInputStream("Here be dragons".bytes)
>>
>> println
>> MessageDigest.getInstance("SHA1").digest(content.bytes).encodeHex()
>>
>>
>>
>> //If the content might be arbitrarily long:
>>
>> content = new ByteArrayInputStream("Here be dragons".bytes)
>>
>> def digest = MessageDigest.getInstance("SHA1")
>>
>> content.eachByte(4096) { bytes, len ->
>>
>> digest.update(bytes, 0, len)
>>
>> }
>>
>> println digest.digest().encodeHex()
>>
>>
>>
>> Jason
>>
>>
>>
>> *From:* Gerald Wiltse [mailto:jerrywiltse@gmail.com]
>> *Sent:* Friday, March 04, 2016 9:18 AM
>> *To:* users@groovy.apache.org
>> *Subject:* Groovy Hash Calculations
>>
>>
>>
>> Hello All,
>>
>>
>>
>> I have this block, it's pretty compressed, just wondering if there is a
>> more groovy way to handle reading the buffer and computing the hash.
>>
>>
>>
>> def messageDigest = MessageDigest.getInstance("SHA1")
>>
>> def dis = new DigestInputStream(content, messageDigest)
>>
>> byte[] buffer = new byte[1024];
>>
>> while (dis.read(buffer) != -1) {}
>>
>> def sha1Hex = new BigInteger(1,
>> messageDigest.digest()).toString(16).padLeft(40, '0')
>>
>>
>>
>>
>> Gerald R. Wiltse
>> jerrywiltse@gmail.com
>>
>>
>> ------------------------------
>>
>> This email message and any attachments are for the sole use of the
>> intended recipient(s). Any unauthorized review, use, disclosure or
>> distribution is prohibited. If you are not the intended recipient, please
>> contact the sender by reply email and destroy all copies of the original
>> message and any attachments.
>>
>>
>>
>
>
Re: Groovy Hash Calculations
Posted by Gerald Wiltse <je...@gmail.com>.
Ok, returning back to this, my test case did not want to save the file,
only calculate the hash as memory-efficiently as possible without
buffereing. Mission accomplished.
However now my real implementation does want to save and hash, again as
memory-efficiently as possible.
This is what I've created so far.
First, getting error at the "while()" loop:
Caught: java.lang.NullPointerException
java.lang.NullPointerException
at java_io_FilterInputStream$read.call(Unknown Source)
Second, I'm really unsatisfied with it.
1. Declaring all the variables before the loop is... really verbose
2. It seems like the hash and file write operations should be separated.
Does anyone have any suggestions?
def baseDir = new File("c:/data")
File localFile
byte[] buffer
DigestInputStream dis
MessageDigest digest
ByteArrayInputStream bais
jarList.each{Map jarMetadata ->
content.filePath = jarMetadata['path']
bais = content.downloadContent(true, [bt_package: testPkg])
localFile = new File(baseDir, jarMetadata['path'])
localFile.parentFile.mkdirs()
localFile.withOutputStream {fos->
buffer = new byte[1024]
dis = new DigestInputStream(bais, digest)
digest = MessageDigest.getInstance("SHA1")
while (dis.read(buffer) != -1) {
fos.write(buffer)
}
}
assert digest.digest().encodeHex() == jarMetadata['sha1']
}
Gerald R. Wiltse
jerrywiltse@gmail.com
On Fri, Mar 4, 2016 at 11:30 AM, Winnebeck, Jason <
Jason.Winnebeck@windstream.com> wrote:
> Only the “short” solution I wrote involved buffering to memory. The “long”
> solution I wrote involves no buffering. The DigestInputStream is not
> related to whether or not there is buffering, all it does is it lets you
> read the stream and get a digest at the same time. If you are just throwing
> out the data, there’s no need for the DigestInputStream. DigestInputStream
> just takes the result of every read call and sends the bytes to
> MessageDigest#update before returning the data. DigestInputStream makes
> sense if you were, for example, passing that input stream to another method
> that wrote the content to a file then you wanted to get the digest after
> the file write was complete.
>
>
>
> Jason
>
>
>
> *From:* Gerald Wiltse [mailto:jerrywiltse@gmail.com]
> *Sent:* Friday, March 04, 2016 10:08 AM
> *To:* users@groovy.apache.org
> *Subject:* Re: Groovy Hash Calculations
>
>
>
> I'm trying to verify the sha1 hash on a file download without saving it to
> disk, and without buffering the whole thing. I think this solution might
> buffer all the data into "content" before going into the eachByte loop. I
> thought that was the reason for the DigestInputStream. Do you know if this
> is correct?
>
>
> Gerald R. Wiltse
> jerrywiltse@gmail.com
>
>
>
>
>
> On Fri, Mar 4, 2016 at 9:40 AM, Winnebeck, Jason <
> Jason.Winnebeck@windstream.com> wrote:
>
> Here is how I would do it. I provide both a “short” solution and a “long”
> one. I would use the “short” solution if I was making for example a
> developer only tool and I knew I was only hashing small things for example
> a configuration file in a build script and want a one-liner. Otherwise I’d
> use the “long” version.
>
>
>
> //If the content is guaranteed to be short:
>
> def content = new ByteArrayInputStream("Here be dragons".bytes)
>
> println MessageDigest.getInstance("SHA1").digest(content.bytes).encodeHex()
>
>
>
> //If the content might be arbitrarily long:
>
> content = new ByteArrayInputStream("Here be dragons".bytes)
>
> def digest = MessageDigest.getInstance("SHA1")
>
> content.eachByte(4096) { bytes, len ->
>
> digest.update(bytes, 0, len)
>
> }
>
> println digest.digest().encodeHex()
>
>
>
> Jason
>
>
>
> *From:* Gerald Wiltse [mailto:jerrywiltse@gmail.com]
> *Sent:* Friday, March 04, 2016 9:18 AM
> *To:* users@groovy.apache.org
> *Subject:* Groovy Hash Calculations
>
>
>
> Hello All,
>
>
>
> I have this block, it's pretty compressed, just wondering if there is a
> more groovy way to handle reading the buffer and computing the hash.
>
>
>
> def messageDigest = MessageDigest.getInstance("SHA1")
>
> def dis = new DigestInputStream(content, messageDigest)
>
> byte[] buffer = new byte[1024];
>
> while (dis.read(buffer) != -1) {}
>
> def sha1Hex = new BigInteger(1,
> messageDigest.digest()).toString(16).padLeft(40, '0')
>
>
>
>
> Gerald R. Wiltse
> jerrywiltse@gmail.com
>
>
> ------------------------------
>
> This email message and any attachments are for the sole use of the
> intended recipient(s). Any unauthorized review, use, disclosure or
> distribution is prohibited. If you are not the intended recipient, please
> contact the sender by reply email and destroy all copies of the original
> message and any attachments.
>
>
>
Re: Groovy Hash Calculations
Posted by Gerald Wiltse <je...@gmail.com>.
Thank you very much Jason, that helps a lot.
Gerald R. Wiltse
jerrywiltse@gmail.com
On Fri, Mar 4, 2016 at 11:30 AM, Winnebeck, Jason <
Jason.Winnebeck@windstream.com> wrote:
> Only the “short” solution I wrote involved buffering to memory. The “long”
> solution I wrote involves no buffering. The DigestInputStream is not
> related to whether or not there is buffering, all it does is it lets you
> read the stream and get a digest at the same time. If you are just throwing
> out the data, there’s no need for the DigestInputStream. DigestInputStream
> just takes the result of every read call and sends the bytes to
> MessageDigest#update before returning the data. DigestInputStream makes
> sense if you were, for example, passing that input stream to another method
> that wrote the content to a file then you wanted to get the digest after
> the file write was complete.
>
>
>
> Jason
>
>
>
> *From:* Gerald Wiltse [mailto:jerrywiltse@gmail.com]
> *Sent:* Friday, March 04, 2016 10:08 AM
> *To:* users@groovy.apache.org
> *Subject:* Re: Groovy Hash Calculations
>
>
>
> I'm trying to verify the sha1 hash on a file download without saving it to
> disk, and without buffering the whole thing. I think this solution might
> buffer all the data into "content" before going into the eachByte loop. I
> thought that was the reason for the DigestInputStream. Do you know if this
> is correct?
>
>
> Gerald R. Wiltse
> jerrywiltse@gmail.com
>
>
>
>
>
> On Fri, Mar 4, 2016 at 9:40 AM, Winnebeck, Jason <
> Jason.Winnebeck@windstream.com> wrote:
>
> Here is how I would do it. I provide both a “short” solution and a “long”
> one. I would use the “short” solution if I was making for example a
> developer only tool and I knew I was only hashing small things for example
> a configuration file in a build script and want a one-liner. Otherwise I’d
> use the “long” version.
>
>
>
> //If the content is guaranteed to be short:
>
> def content = new ByteArrayInputStream("Here be dragons".bytes)
>
> println MessageDigest.getInstance("SHA1").digest(content.bytes).encodeHex()
>
>
>
> //If the content might be arbitrarily long:
>
> content = new ByteArrayInputStream("Here be dragons".bytes)
>
> def digest = MessageDigest.getInstance("SHA1")
>
> content.eachByte(4096) { bytes, len ->
>
> digest.update(bytes, 0, len)
>
> }
>
> println digest.digest().encodeHex()
>
>
>
> Jason
>
>
>
> *From:* Gerald Wiltse [mailto:jerrywiltse@gmail.com]
> *Sent:* Friday, March 04, 2016 9:18 AM
> *To:* users@groovy.apache.org
> *Subject:* Groovy Hash Calculations
>
>
>
> Hello All,
>
>
>
> I have this block, it's pretty compressed, just wondering if there is a
> more groovy way to handle reading the buffer and computing the hash.
>
>
>
> def messageDigest = MessageDigest.getInstance("SHA1")
>
> def dis = new DigestInputStream(content, messageDigest)
>
> byte[] buffer = new byte[1024];
>
> while (dis.read(buffer) != -1) {}
>
> def sha1Hex = new BigInteger(1,
> messageDigest.digest()).toString(16).padLeft(40, '0')
>
>
>
>
> Gerald R. Wiltse
> jerrywiltse@gmail.com
>
>
> ------------------------------
>
> This email message and any attachments are for the sole use of the
> intended recipient(s). Any unauthorized review, use, disclosure or
> distribution is prohibited. If you are not the intended recipient, please
> contact the sender by reply email and destroy all copies of the original
> message and any attachments.
>
>
>
RE: Groovy Hash Calculations
Posted by "Winnebeck, Jason" <Ja...@windstream.com>.
Only the “short” solution I wrote involved buffering to memory. The “long” solution I wrote involves no buffering. The DigestInputStream is not related to whether or not there is buffering, all it does is it lets you read the stream and get a digest at the same time. If you are just throwing out the data, there’s no need for the DigestInputStream. DigestInputStream just takes the result of every read call and sends the bytes to MessageDigest#update before returning the data. DigestInputStream makes sense if you were, for example, passing that input stream to another method that wrote the content to a file then you wanted to get the digest after the file write was complete.
Jason
From: Gerald Wiltse [mailto:jerrywiltse@gmail.com]
Sent: Friday, March 04, 2016 10:08 AM
To: users@groovy.apache.org
Subject: Re: Groovy Hash Calculations
I'm trying to verify the sha1 hash on a file download without saving it to disk, and without buffering the whole thing. I think this solution might buffer all the data into "content" before going into the eachByte loop. I thought that was the reason for the DigestInputStream. Do you know if this is correct?
Gerald R. Wiltse
jerrywiltse@gmail.com<ma...@gmail.com>
On Fri, Mar 4, 2016 at 9:40 AM, Winnebeck, Jason <Ja...@windstream.com>> wrote:
Here is how I would do it. I provide both a “short” solution and a “long” one. I would use the “short” solution if I was making for example a developer only tool and I knew I was only hashing small things for example a configuration file in a build script and want a one-liner. Otherwise I’d use the “long” version.
//If the content is guaranteed to be short:
def content = new ByteArrayInputStream("Here be dragons".bytes)
println MessageDigest.getInstance("SHA1").digest(content.bytes).encodeHex()
//If the content might be arbitrarily long:
content = new ByteArrayInputStream("Here be dragons".bytes)
def digest = MessageDigest.getInstance("SHA1")
content.eachByte(4096) { bytes, len ->
digest.update(bytes, 0, len)
}
println digest.digest().encodeHex()
Jason
From: Gerald Wiltse [mailto:jerrywiltse@gmail.com<ma...@gmail.com>]
Sent: Friday, March 04, 2016 9:18 AM
To: users@groovy.apache.org<ma...@groovy.apache.org>
Subject: Groovy Hash Calculations
Hello All,
I have this block, it's pretty compressed, just wondering if there is a more groovy way to handle reading the buffer and computing the hash.
def messageDigest = MessageDigest.getInstance("SHA1")
def dis = new DigestInputStream(content, messageDigest)
byte[] buffer = new byte[1024];
while (dis.read(buffer) != -1) {}
def sha1Hex = new BigInteger(1, messageDigest.digest()).toString(16).padLeft(40, '0')
Gerald R. Wiltse
jerrywiltse@gmail.com<ma...@gmail.com>
________________________________
This email message and any attachments are for the sole use of the intended recipient(s). Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message and any attachments.
Re: Groovy Hash Calculations
Posted by Gerald Wiltse <je...@gmail.com>.
I'm trying to verify the sha1 hash on a file download without saving it to
disk, and without buffering the whole thing. I think this solution might
buffer all the data into "content" before going into the eachByte loop. I
thought that was the reason for the DigestInputStream. Do you know if this
is correct?
Gerald R. Wiltse
jerrywiltse@gmail.com
On Fri, Mar 4, 2016 at 9:40 AM, Winnebeck, Jason <
Jason.Winnebeck@windstream.com> wrote:
> Here is how I would do it. I provide both a “short” solution and a “long”
> one. I would use the “short” solution if I was making for example a
> developer only tool and I knew I was only hashing small things for example
> a configuration file in a build script and want a one-liner. Otherwise I’d
> use the “long” version.
>
>
>
> //If the content is guaranteed to be short:
>
> def content = new ByteArrayInputStream("Here be dragons".bytes)
>
> println MessageDigest.getInstance("SHA1").digest(content.bytes).encodeHex()
>
>
>
> //If the content might be arbitrarily long:
>
> content = new ByteArrayInputStream("Here be dragons".bytes)
>
> def digest = MessageDigest.getInstance("SHA1")
>
> content.eachByte(4096) { bytes, len ->
>
> digest.update(bytes, 0, len)
>
> }
>
> println digest.digest().encodeHex()
>
>
>
> Jason
>
>
>
> *From:* Gerald Wiltse [mailto:jerrywiltse@gmail.com]
> *Sent:* Friday, March 04, 2016 9:18 AM
> *To:* users@groovy.apache.org
> *Subject:* Groovy Hash Calculations
>
>
>
> Hello All,
>
>
>
> I have this block, it's pretty compressed, just wondering if there is a
> more groovy way to handle reading the buffer and computing the hash.
>
>
>
> def messageDigest = MessageDigest.getInstance("SHA1")
>
> def dis = new DigestInputStream(content, messageDigest)
>
> byte[] buffer = new byte[1024];
>
> while (dis.read(buffer) != -1) {}
>
> def sha1Hex = new BigInteger(1,
> messageDigest.digest()).toString(16).padLeft(40, '0')
>
>
>
>
> Gerald R. Wiltse
> jerrywiltse@gmail.com
>
>
> ------------------------------
> This email message and any attachments are for the sole use of the
> intended recipient(s). Any unauthorized review, use, disclosure or
> distribution is prohibited. If you are not the intended recipient, please
> contact the sender by reply email and destroy all copies of the original
> message and any attachments.
>
Re: Groovy Hash Calculations
Posted by Gerald Wiltse <je...@gmail.com>.
Ok, that seems like a really GOSU trick. Might try to try that when i get
back there.
Gerald R. Wiltse
jerrywiltse@gmail.com
On Fri, Mar 4, 2016 at 1:03 PM, Nelson, Erick [HDS] <
Erick.Nelson@hdsupply.com> wrote:
> I had to do this in one of my apps.
>
> I used java’s nameUUIDFromBytes from java.util
>
>
>
> UUID.nameUUIDFromBytes(map.v as byte[]).toString()
>
>
>
> If I read the docs right, it uses sha-1 under the hood.
>
>
>
> *Erick Nelson*
>
> *Senior Developer *|* IT Application Development*
>
> *HD Supply Facilities Maintenance*
>
> O: 858-831-2209
>
> C: 760-473-7542
>
> H: 760-930-0461
>
> Erick.Nelson@hdsupply.com <Bi...@hdsupply.com>
>
>
>
> *From:* Winnebeck, Jason [mailto:Jason.Winnebeck@windstream.com]
> *Sent:* Friday, March 04, 2016 6:40 AM
> *To:* users@groovy.apache.org
> *Subject:* RE: Groovy Hash Calculations
>
>
>
> Here is how I would do it. I provide both a “short” solution and a “long”
> one. I would use the “short” solution if I was making for example a
> developer only tool and I knew I was only hashing small things for example
> a configuration file in a build script and want a one-liner. Otherwise I’d
> use the “long” version.
>
>
>
> //If the content is guaranteed to be short:
>
> def content = new ByteArrayInputStream("Here be dragons".bytes)
>
> println MessageDigest.getInstance("SHA1").digest(content.bytes).encodeHex()
>
>
>
> //If the content might be arbitrarily long:
>
> content = new ByteArrayInputStream("Here be dragons".bytes)
>
> def digest = MessageDigest.getInstance("SHA1")
>
> content.eachByte(4096) { bytes, len ->
>
> digest.update(bytes, 0, len)
>
> }
>
> println digest.digest().encodeHex()
>
>
>
> Jason
>
>
>
> *From:* Gerald Wiltse [mailto:jerrywiltse@gmail.com
> <je...@gmail.com>]
> *Sent:* Friday, March 04, 2016 9:18 AM
> *To:* users@groovy.apache.org
> *Subject:* Groovy Hash Calculations
>
>
>
> Hello All,
>
>
>
> I have this block, it's pretty compressed, just wondering if there is a
> more groovy way to handle reading the buffer and computing the hash.
>
>
>
> def messageDigest = MessageDigest.getInstance("SHA1")
>
> def dis = new DigestInputStream(content, messageDigest)
>
> byte[] buffer = new byte[1024];
>
> while (dis.read(buffer) != -1) {}
>
> def sha1Hex = new BigInteger(1,
> messageDigest.digest()).toString(16).padLeft(40, '0')
>
>
>
>
> Gerald R. Wiltse
> jerrywiltse@gmail.com
>
>
> ------------------------------
>
> This email message and any attachments are for the sole use of the
> intended recipient(s). Any unauthorized review, use, disclosure or
> distribution is prohibited. If you are not the intended recipient, please
> contact the sender by reply email and destroy all copies of the original
> message and any attachments.
>
RE: Groovy Hash Calculations
Posted by "Nelson, Erick [HDS]" <Er...@hdsupply.com>.
I had to do this in one of my apps.
I used java’s nameUUIDFromBytes from java.util
UUID.nameUUIDFromBytes(map.v as byte[]).toString()
If I read the docs right, it uses sha-1 under the hood.
Erick Nelson
Senior Developer | IT Application Development
HD Supply Facilities Maintenance
O: 858-831-2209
C: 760-473-7542
H: 760-930-0461
Erick.Nelson@hdsupply.com<ma...@hdsupply.com>
From: Winnebeck, Jason [mailto:Jason.Winnebeck@windstream.com]
Sent: Friday, March 04, 2016 6:40 AM
To: users@groovy.apache.org
Subject: RE: Groovy Hash Calculations
Here is how I would do it. I provide both a “short” solution and a “long” one. I would use the “short” solution if I was making for example a developer only tool and I knew I was only hashing small things for example a configuration file in a build script and want a one-liner. Otherwise I’d use the “long” version.
//If the content is guaranteed to be short:
def content = new ByteArrayInputStream("Here be dragons".bytes)
println MessageDigest.getInstance("SHA1").digest(content.bytes).encodeHex()
//If the content might be arbitrarily long:
content = new ByteArrayInputStream("Here be dragons".bytes)
def digest = MessageDigest.getInstance("SHA1")
content.eachByte(4096) { bytes, len ->
digest.update(bytes, 0, len)
}
println digest.digest().encodeHex()
Jason
From: Gerald Wiltse [mailto:jerrywiltse@gmail.com]
Sent: Friday, March 04, 2016 9:18 AM
To: users@groovy.apache.org<ma...@groovy.apache.org>
Subject: Groovy Hash Calculations
Hello All,
I have this block, it's pretty compressed, just wondering if there is a more groovy way to handle reading the buffer and computing the hash.
def messageDigest = MessageDigest.getInstance("SHA1")
def dis = new DigestInputStream(content, messageDigest)
byte[] buffer = new byte[1024];
while (dis.read(buffer) != -1) {}
def sha1Hex = new BigInteger(1, messageDigest.digest()).toString(16).padLeft(40, '0')
Gerald R. Wiltse
jerrywiltse@gmail.com<ma...@gmail.com>
________________________________
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RE: Groovy Hash Calculations
Posted by "Winnebeck, Jason" <Ja...@windstream.com>.
Here is how I would do it. I provide both a “short” solution and a “long” one. I would use the “short” solution if I was making for example a developer only tool and I knew I was only hashing small things for example a configuration file in a build script and want a one-liner. Otherwise I’d use the “long” version.
//If the content is guaranteed to be short:
def content = new ByteArrayInputStream("Here be dragons".bytes)
println MessageDigest.getInstance("SHA1").digest(content.bytes).encodeHex()
//If the content might be arbitrarily long:
content = new ByteArrayInputStream("Here be dragons".bytes)
def digest = MessageDigest.getInstance("SHA1")
content.eachByte(4096) { bytes, len ->
digest.update(bytes, 0, len)
}
println digest.digest().encodeHex()
Jason
From: Gerald Wiltse [mailto:jerrywiltse@gmail.com]
Sent: Friday, March 04, 2016 9:18 AM
To: users@groovy.apache.org
Subject: Groovy Hash Calculations
Hello All,
I have this block, it's pretty compressed, just wondering if there is a more groovy way to handle reading the buffer and computing the hash.
def messageDigest = MessageDigest.getInstance("SHA1")
def dis = new DigestInputStream(content, messageDigest)
byte[] buffer = new byte[1024];
while (dis.read(buffer) != -1) {}
def sha1Hex = new BigInteger(1, messageDigest.digest()).toString(16).padLeft(40, '0')
Gerald R. Wiltse
jerrywiltse@gmail.com<ma...@gmail.com>
----------------------------------------------------------------------
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