Can I load an RData file while bypassing loading the namespaces?
Let's say some of my users cannot alter their R environments, but I need them to be able to open up RData files. These environment files require a package to be loaded (httpuv to be exact). We don't care about the package, we don't need its capabilities, we just need to get at the data. Is there a way to either force R to bypass loading namespaces when loading the RData file, or force it to save it without namespace dependencies at the originating end? Thanks.
To reproduce, install Shiny. Create and save a some R objects to the server's file system from within a Shiny applet as an RData file. Copy the file over to a computer that doesn't have Shiny or the httpuv package installed. Try loading the RData file, even if the actual objects you saved are completely ordinary data.frames that have nothing to do with Shiny or httpuv.
I did strings on the RData, and the damn thing is full of references to httpuv. The software is loading the file and then actively deciding to not continue in the internal loadFromConn2() function. Therefore there must be a way to make it stop doing so.
Really @baptiste should get credit for the link in his comment to some general solutions, especially the R CMD INSTALL --fake trick, and I will accept that if he reposts it as an answer. That is why I am not accepting the following answer of my own to the specific problem that caused it in my case, but I am posting my answer in case it helps someone else.
Some of the objects I was saving were lm fitted objects. Those contain formula/terms objects (at least two each, for some reason... maybe because they've been through stepAIC ), and those formulas in turn each have an environment attribute. The environment attribute is .GlobalEnv which probably does contain copies of package functions someplace. When I dug through the objects inside the fitted models, and then the objects inside all the attributes of those objects, and then the objects inside the attributes of the attributes of those objects... and set every environment attribute I could find to NULL, eventually I was able to save that fitted model to a file that could be opened from a different R installation without getting the error about not being able to load a namespace.
I suppose I could also write a function to iterate through the objects within a fitted model, and their attributes, and remove environments but that sounds ugly and dangerous. Maybe there is a way to force formulas and fitted models not to retain environments, and that will be better. For the time being, instead of saving fitted models, I will save their call attributes after scrubbing any environment attributes I might find there. If that doesn't work, I'll deparse them into character strings.
PS: I used the RDS format and haven't yet tested it with RData, but I suspect that the problem was the saving of the evalution environment in some of the attributes, and had nothing to do with the format in which the objects get saved. I'll post an update if it turns out that this doesn't also work with RData.
PPS: I suspect I'm not the only one here who's hearing about the R CMD INSTALL --fake trick for the first time, and perhaps the word should be spread about this... because to the extent other R users don't know about it, this remains an obvious vector for denial-of-service attacks against R!
I will accept my own answer to get rid of the SO auto-nagger, but will unaccept it and accept @baptiste if they make it possible for me to do so by posting it as an answer. Thanks.
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