Just after sending, I realized that you may be running a program like
"app.rkt" directly with `racket`, and then trying to deserialize from
an application created with `raco exe`. That would fail in much the way
you describe for my example.
If that's the problem, then one possible solution is to generate the
serialized data after creating an executable. Creating the data that
way might not be desirable or practical, though.
Another approach is to use a collection/package. When you create an
executable, `racket` goes out of its way to hide path information from
the original context; that's why data serialized based on running a
file will no deserialize in a `raco exe` executable, because the only
identity of the `serializable-struct` declaration is the filesystem
path of its containing module. In contrast to filesystem path, `raco
exe` preserves collection-mapping information. So, if you serialized
data based on a module referenced through a collection path, it will
work for the `raco exe` executable.
Concretely:
* Put "app.rkt" in a collection/package. I'll call it "app":
$ mkdir app
$ mv app.rkt words.rkt app/
$ raco pkg install app/
* Run the application using a module path, as opposed to a filesystem
path:
$ racket -l app/app
((3) 1 (((lib "app/words.rkt") ....)
# Not this way:
$ racket app/app.rkt
((3) 1 ((#"/tmp/app/words.rkt" .....)
* Unfortunately, `raco exe` doesn't currently know how to make an
executable based on a module path. So, make a module that refers to
"app.rkt" through it's module path:
go.rkt:
#lang racket/base
(require app/app)
Then create an executable from "go.rkt":
$ raco exe go.rkt
$ raco dist go-dist go
$ ./go-dist/bin/go
That `./go-dist/bin/go` will work with serialized data produced by
`racket -l app/app`.
Hope that helps,
Matthew
At Sat, 13 Aug 2016 16:25:44 -0600, Matthew Flatt wrote:
> I think we need more of your program to help. In particular, I don't
> know what you have in mind with `(define-namespace-anchor a)`, and I
> wonder whether your program uses `load` or `dynamic-require`.
>
>
> I tried completing your example with
>
> app.rkt:
>
> #lang racket
> (require "words.rkt"
> racket/serialize)
>
> ;; write serialized
> (writeln (serialize (word 1 2)))
> ;; read something that must have been previously serialized
> (deserialize (read (current-input-port)))
>
>
> words.rkt:
>
> #lang racket
> (require racket/serialize)
> (provide (struct-out word))
>
> (serializable-struct word
> (type
> ecc.))
>
> but that works as expected, where the serialized output has something
> like "#%embedded:g2140:words" instead of a path.
>
>
> At Fri, 12 Aug 2016 05:53:35 -0700 (PDT), rumpz wrote:
> > app.rkt:
> >
> > #lang racket
> > (require "words.rkt"
> > web-server/servlet)
> >
> > ....
> >
> >
> > words.rkt:
> >
> > #lang racket
> > (require racket/serialize)
> > (provide (struct-out word) save-words load-words decline)
> >
> > (serializable-struct word
> > (type
> > ecc.))
> >
> > (define-namespace-anchor a)
> > (define ns (namespace-anchor->namespace a))
> >
> > ....
> >
> >
> > If I compile app.rkt with "raco exe app.rkt" and "raco distribute appdir
> > app"
> > and I move the "appdir" directory to another system, when I run ./app it
> > crashes with this error:
> >
> > default-load-handler: cannot open module file
> > module path: #<path:/home/rumpz/webapp/words.rkt>
> > path: /home/rumpz/webapp/words.rkt
> > system error: No such file or directory; errno=2
> > context...:
> > standard-module-name-resolver
> > /usr/share/racket/collects/racket/private/serialize.rkt:654:8: loop
> > /usr/share/racket/collects/racket/private/serialize.rkt:649:2:
> > deserialize
> > #%mzc:app: [running body]
> >
> >
> > Even if I don't move from my system but just rename words.rkt, it still
> > crashes. From the examples and the documentation I assumed that raco
> > automatically included required modules, but it looks like it's just
> > looking
> > for the .rkt file (and even with the exact path that it has on the original
> > system). What am I doing wrong?
> >
> > Also, a secondary problem with modules that may be related: I've tried to
> make
> > a copy of the "webapp" directory, called webapp2. When I launch app from
> > the
> > new directory, it loads a list of "word" structures from a file I saved
> > them
> > in previously, and try to access them with a "word" field (like
> > "word-type")
> > it crashes with:
> >
> > word-type: contract violation;
> > given value instantiates a different structure type with the same name
> > expected: word?
> > given: #<word>
> >
> > It's like it marked down somewhere that those structs refer to the
> definition
> > of "word" in webapp/words.rkt, and not the one in webapp2/words.rkt
> >
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