Amazon S3 Upload Whats does Key do -

i confused key value should when using amazon s3 here code.

   <form action="http://bucket.s3.amazonaws.com" method="post" enctype="multipart/form-data"> <input type="text" name="key" value="{filename}" /> <input type="text" name="acl" value="public-read" /> <input type="text" name="content-type" value="text/plain" /> <input type="hidden" name="awsaccesskeyid" value="amazon key" /> <input type="hidden" name="policy" value="ewogicjlehbpcmf0aw9uijogijiwmtitmdetmdfumti6mda6mdaumdawwiisciagimnvbmrpdglvbnmioibbciagicb7imj1y2tldci6icjpcihsiywnsijoginb1ymxpyy1yzwfkiib9laogicagwyjlcsisicika2v5iiwgintmawxlbmftzx0ixswkicagifsic3rhcnrzlxdpdggilcaijenvbnrlbnqtvhlwzsisicj0zxh0lyjdlaogif0kfqo=" /> <input type="hidden" name="signature" value="fgwi1jku+hkzkbcil1ed0=" /> <input name="file" type="file" /> <input name="submit" value="upload" type="submit" /> </form> 

ok using service generate policy etc because havent got clue how manually.

http://s3.amazonaws.com/doc/s3-example-code/post/post_sample.html

this works , gives me upload. when upload files call {filename} , not filename says picture.jpg. know down line.

<input type="text" name="key" value="{filename}" /> 

i want take value off filename uploading.

what doing wrong confused.

i have tried leaving blank error.

invalidargumentuser key must have length greater 0

i want work out me????

any please

i know posted question long time ago, might have same question.

key name , path of file uploading.

you can set conditions in policy regarding key, should start with. can keep original file name using value: ${filename} (you missing $)

example: keep original file name, put in folder /docs/

the form:

<form action="http://yourbucketname.s3.amazonaws.com" method="post" enctype="multipart/form-data"> <input type="text" name="key" value="docs/${filename}" /> <input type="text" name="acl" value="public-read" /> <input type="text" name="content-type" value="text/plain" /> <input type="hidden" name="awsaccesskeyid" value="<yourpublickey>" /> <input type="hidden" name="policy" value="<base64_encoded_your_policy>" /> <input type="hidden" name="signature" value="<hmac sha-1 of policy>" /> <input name="file" type="file" /> <input name="submit" value="upload" type="submit" /> </form> 

the policy json

{"expiration": "2013-12-01t12:00:00.000z", "conditions": [ {"acl": "public-read-write" }, {"bucket": "yourbucketname" }, ["starts-with", "$key", "docs/"], ["starts-with", "$content-type", "text/plain"], ] } 

what need do:

• replace yourbucketname in action , policy-json
• base64 encode policy
• set policy in form policy value
• replace awsaccesskeyid in form
• sign encoded policy secret access key using hmac sha-1
• set signature in form signature value