Haskell error handling, log invalid file path to console -

-



as part of this project, i'd validate path of file that's provided passwords, i.e. pwds <- case cfgpasswords of passpath -> (map (just . t.unpack) . lines) <$> readfileutf8 passpath, in case path file not valid i'd log message effect console.

how accomplish in haskell? 

logf' "log level {}" [show loglevel] setloglevel loglevel debugf' "configuration: {}" [show cfg] ncpus <- getnumprocessors logf' "utilizing {} core(s)" [ncpus] setnumcapabilities ncpus pwds <- case cfgpasswords of     passpath -> (map (just . t.unpack) . lines) <$>         readfileutf8 passpath     nothing       -> return $ replicate (length cfgpublickeys) nothing when (length cfgpublickeys /= length cfgprivatekeys) $     errorl' "the same amount of public keys , private keys must specified" when (length cfgpublickeys /= length pwds) $     errorl' "the same amount of passwords must included in passwords file number of private keys. (if private key has no password, include blank line.)" when (cfgport == 0) $     errorl' "a listening port must specified 'port' in configuration file or --port @ runtime"

the idea go right above line when (length cfgpublickeys /= length cfgprivatekeys) $.

i'm not sure have enough information in code snippet deduce precisely what's going on here type signatures.

the project you've linked seems it's written in go?

there appear number of project specific functions you're calling in code example.

for case of 'does file path point file,' you'd like:

checkforafile :: filepath -> io () checkforafile path =     validfile <- doesfileexist path     if validfile        putstrln $ path ++ " file exists"        else putstrln $ path ++ " not file exists"

doesfileexist function available in system.directory library, , canonical way answer question of whether or not filepath points file.

not knowing code doing, can't suggest proper place toss in check, that's enough go on.

if isn't, may suggest trying whet teeth on haskell code has little less going on.





wiki

Comments

Post a Comment

Popular posts from this blog

python - Read npy file directly from S3 StreamingBody -

-
i have many .npy (numpy) , .json files saved in s3, need download , load these files. for json files downloading files , loading dictionary using following code: obj = s3.object(bucket, key) response = obj.get() body = response['body'].read().decode('utf-8') data = json.loads(body) that way avoid writing .json file disk , reading it. now want same .npy files, equivalent? currently downloading file, saving temp file on disk , loading np.load avoid if possible. following https://stackoverflow.com/a/28196540/3509999 : obj = s3.object(bucket, key) io.bytesio(obj.get()["body"].read()) f: # rewind file f.seek(0) arr = np.load(f) wiki
Read more

kotlin - Out-projected type in generic interface prohibits the use of metod with generic parameter -

-
i start using kotlin , defined interface this: interface aadapter<vh : recyclerview.viewholder> { fun oncreateaviewholder(parent: viewgroup): vh fun onbindaviewholder(v: vh, position: int) } and when try use on code: class klasa ( private val adapter: aadapter<*> ) { fun dosth(){ //... val vh = this.adapter.oncreateaviewholder(parent) //on below line error adapter.onbindaviewholder(v, position) //... } } i error out-projected type 'aadapter<*>' prohibits use of 'public abstract fun onbindaviewholder(v: t, position: int): unit i tied add "in" or "out" definition i'm confused. how allow it. replace aadapter<*> aadapter<recyclerview.viewholder> . class klasa ( private val adapter: aadapter<recyclerview.viewholder> ) { // ... because have declared aadapter has type parameter vh type subclass of recyclerview....
Read more

Asterisk AGI Python Script to Dialplan does not work -

-
i'm stuck project have check database of sip extension incoming caller id , dial sip extension. below receive when run script on asterisk cli. -- registered sip '9125' @ 192.168.1.102:50142 > saved useragent "zoiper rv2.8.40" peer 9125 [2017-08-22 13:53:33] notice[5095]: chan_sip.c:24558 handle_response_peerpoke: peer '9125' reachable. (17ms / 2000ms) == using sip rtp tos bits 184 == using sip rtp cos mark 5 -- executing [0112617769@from-trunk:1] answer("sip/obitrunk1-0000000d", "") in new stack > 0x1ca50d0 -- probation passed - setting rtp source address 192.168.1.98:16834 -- executing [0112617769@from-trunk:2] agi("sip/obitrunk1-0000000d", "test.py") in new stack -- launched agi script /var/lib/asterisk/agi-bin/test.py args: ['/var/lib/asterisk/agi-bin/test.py'] env line: agi_request: test.py env line: agi_channel: sip/obitrunk1-0000000d env line: agi_language: en env line: a...
Read more