54 lines
2.2 KiB
Markdown
54 lines
2.2 KiB
Markdown
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# Request Based SFTP API
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The request based API allows for custom backends in a way similar to the http
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package. In order to create a backend you need to implement 4 handler
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interfaces; one for reading, one for writing, one for misc commands and one for
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listing files. Each has 1 required method and in each case those methods take
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the Request as the only parameter and they each return something different.
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These 4 interfaces are enough to handle all the SFTP traffic in a simplified
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manner.
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The Request structure has 5 public fields which you will deal with.
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- Method (string) - string name of incoming call
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- Filepath (string) - POSIX path of file to act on
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- Flags (uint32) - 32bit bitmask value of file open/create flags
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- Attrs ([]byte) - byte string of file attribute data
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- Target (string) - target path for renames and sym-links
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Below are the methods and a brief description of what they need to do.
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### Fileread(*Request) (io.Reader, error)
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Handler for "Get" method and returns an io.Reader for the file which the server
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then sends to the client.
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### Filewrite(*Request) (io.Writer, error)
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Handler for "Put" method and returns an io.Writer for the file which the server
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then writes the uploaded file to. The file opening "pflags" are currently
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preserved in the Request.Flags field as a 32bit bitmask value. See the [SFTP
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spec](https://filezilla-project.org/specs/draft-ietf-secsh-filexfer-02.txt#section-6.3) for
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details.
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### Filecmd(*Request) error
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Handles "SetStat", "Rename", "Rmdir", "Mkdir" and "Symlink" methods. Makes the
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appropriate changes and returns nil for success or an filesystem like error
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(eg. os.ErrNotExist). The attributes are currently propagated in their raw form
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([]byte) and will need to be unmarshalled to be useful. See the respond method
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on sshFxpSetstatPacket for example of you might want to do this.
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### Fileinfo(*Request) ([]os.FileInfo, error)
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Handles "List", "Stat", "Readlink" methods. Gathers/creates FileInfo structs
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with the data on the files and returns in a list (list of 1 for Stat and
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Readlink).
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## TODO
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- Add support for API users to see trace/debugging info of what is going on
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inside SFTP server.
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- Unmarshal the file attributes into a structure on the Request object.
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