Using the code-free app

Launching the app

The app needs the suggested packages shiny, bslib and callr, and ggplot2 for the plots. With those installed, one call opens it.

library(scopusflow)
run_app()

By default it listens only on 127.0.0.1, so it is reachable from your own machine alone, and it opens your browser at the address it prints. Passing launch.browser = FALSE leaves the browser to you, and port fixes the port when you need a stable address.

Demo mode

Demo mode is switched on when the app opens, so you can walk the whole flow with no key at all. With it on, the harvest is simulated, the live terminal still streams its per-cell progress, the tables and plots still render, and the Compare topics tab still draws a figure. It is the quickest way to learn where each control sits before you spend any quota. The records come from example_records, the corpus of 138 real journal articles the package bundles because Scopus records may not be redistributed, so every panel is exercised on real titles, DOIs, journals and citation counts, and the by-year chart shows a real publication curve with the shape the literature actually has. That corpus spans 2015 to 2024, so a year range reaching outside it is drawn from the nearest year it holds. Only the topic comparison is synthesised, since it counts whole literatures, which no set of records in hand can answer for. When you are ready for real results, paste your Scopus key into the field at the top of the sidebar and switch Demo mode off. The key stays in the running session and is never written into the generated script.

Describing and sizing a search

The sidebar is where you describe the search. You enter your terms, choose which field to search in, set a year range, and pick the level of detail. Partitioning by year is recommended and switched on by default, because it keeps each cell under the API’s offset ceiling, the same reasoning behind a partitioned scopus_plan() in code. Check size runs a cheap count first, the same one scopus_count() performs, so you can see how much a query would retrieve before committing to it. In demo mode it reports instead how many records it would draw from the bundled corpus.

The scopusflow sidebar as the app opens, with a Scopus API key field, a Demo mode checkbox switched on, the search terms “graphene supercapacitor”, a Search in selector reading “Title, abstract, keywords”, a Partition by year checkbox, a year-range slider set to 2021 to 2026, a STANDARD or COMPLETE detail choice, a maximum records per year field, and the Check size, Fetch records and Cancel buttons.

Fetching, with a live terminal

Fetch records starts the harvest in a background process, so the app stays responsive while it works. The Live terminal panel tails the worker’s output, streaming a line as each year-cell completes, and a progress bar tracks how far through the plan the run has reached. Cancel ends the background process at once, which does abandon whatever cell was in flight. Every cell that had already finished was checkpointed as it completed, and a checkpoint is written to a temporary file and renamed into place, so a cancelled run leaves the cache whole and a later run resumes from it. Internally the app builds a scopus_plan() from your choices and hands it to scopus_fetch_plan() with a cache directory and resume turned on, so an interrupted or quota-limited run picks up where it left off.

The Retrieval panel part-way through a demo-mode harvest. A note reads “Demo plan: 6 year-cells; would draw 57 records from the bundled corpus”, a label reads “Fetching cell 4 of 6” above a progress bar at 50%, and the expanded Live terminal below shows four lines, one for each cell the run has reached, each reading “Cell n/6: demo records for graphene supercapacitor” with the year.

The reproducible code panel

The Reproducible code panel is what turns the app into a tutorial. It mirrors every choice you make, the query, the field, the years, whether you partition by year, and the Compare topics options, and rewrites a runnable R script as you go. Change a control and the script updates at once, so you can see exactly which argument each choice sets. The key never appears in the script. The panel notes that it is read from the SCOPUS_API_KEY environment variable, so a script you share carries the method but not your credentials. Download script saves exactly what you see.

The Reproducible code panel, holding the script the app has written from the choices in the sidebar: a library call, a scopus_plan() with the query, years, field and yearly partition, a scopus_count() to size the search, a scopus_fetch_plan() with a cache directory and resume set, and scopus_top() and autoplot() calls to inspect the result. A comment records that the key is read from the SCOPUS_API_KEY environment variable and never written into the script.

Reading the results

When the run finishes, the Results tabs come to life. Records shows a table of titles, years, sources and citations. By year draws the publications-per-year trend through autoplot(). Top sources and Top authors tally the most frequent of each with scopus_top() and plot_scopus_top(). Every figure is drawn by the same library functions you would call from a script, so the app shows you nothing you could not reproduce.

The Results panel with tabs for Records, By year, Top sources, Top authors, Compare topics and Export. The Records tab is open, showing the first rows of a table of titles, years, journals and citation counts from the demo harvest. The first row reads “Recent trends in graphene supercapacitors: from large area to microsupercapacitors”, published in Sustainable Energy & Fuels in 2021 with 211 citations, and the rows below it are likewise real articles from the bundled corpus.

Comparing topics

The Compare topics tab asks a different question from a harvest. It retrieves no records at all, and measures instead how a set of sub-topics co-occur with your search over time, as a share of it, with your search terms acting as the reference topic. You enter comma-separated comparison terms, optionally pick one to highlight, and toggle the stability band and whether record counts appear on the labels. Because each term needs one count request per year, the tab shows how many requests a comparison will make and warns when the grid grows large. In demo mode the comparison is synthesised so you can see the figure offline. With a key it calls scopus_compare_topics() and draws the result with plot_scopus_comparison(), the same figure the package produces, and a Comparison download saves the underlying numbers as a CSV.

Exporting

Every result the app shows comes with one-click export. The records can be saved as an RDS file, as a clean DOI list, and as BibTeX and RIS for a reference manager such as Zotero or EndNote, drawn from as_bibtex() and as_ris(), and as a PRISMA-S search record in Markdown, drawn from scopus_search_report(). In demo mode that record carries no plan or retrieval time, and says so, since the records on screen were replayed from the bundled corpus and never retrieved. The comparison can be saved as a CSV. None of this contacts the API again, because it works on results already in hand. Between the downloaded script and the exported records, a session in the app leaves you with both the data and the code that produced it.

Beyond the app

Anything you can do in the app you can also do from code, but the reverse does not hold. The app covers planning, retrieval and the trend, top and comparison analyses, and the package goes further. scopus_intersections() counts how a set of named concepts and their intersections overlap in the literature, and plot_scopus_intersections() draws the result. scopus_abstract() retrieves abstract text and richer metadata than the Search API returns, and scopus_corpus() builds on it to give a harvest author keywords and structured references for tools further downstream. When a session in the app has taken you as far as it goes, the downloaded script is the place to carry on from.