aboutsummaryrefslogtreecommitdiffstats
path: root/fatcat_scholar/web.py
blob: 4887aa6772dfd158180d654a25b4106929a6a6e0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
"""
This contains the FastAPI web application and RESTful API.

So far there are few endpoints, so we just put them all here!
"""

import logging
from typing import Optional, Any, List, Dict

from pydantic import BaseModel
import babel.numbers
import babel.support
from fastapi import FastAPI, APIRouter, Request, Depends, Response, HTTPException
from fastapi.staticfiles import StaticFiles
from fastapi.responses import PlainTextResponse, JSONResponse, FileResponse
from fastapi.middleware.cors import CORSMiddleware
import sentry_sdk
from sentry_sdk.integrations.asgi import SentryAsgiMiddleware
from starlette_prometheus import metrics, PrometheusMiddleware
from starlette.exceptions import HTTPException as StarletteHTTPException

from fatcat_scholar.config import settings, GIT_REVISION
from fatcat_scholar.hacks import Jinja2Templates, parse_accept_lang
from fatcat_scholar.search import process_query, FulltextQuery, FulltextHits
from fatcat_scholar.schema import ScholarDoc


logger = logging.getLogger()

I18N_LANG_TRANSLATIONS = [
    "ar",
    "de",
    "es",
    "fa",
    "fr",
    "hr",
    "it",
    "nb",
    "nl",
    "pt",
    "ru",
    "zh",
]
I18N_LANG_OPTIONS = I18N_LANG_TRANSLATIONS + [
    settings.I18N_LANG_DEFAULT,
]


class LangPrefix:
    """
    Looks for a two-character language prefix.

    If there is no such prefix, in the future it could also look at the
    Accept-Language header and try to infer a language from that, while not
    setting the prefix code.
    """

    def __init__(self, request: Request):
        self.prefix: str = ""
        self.code: str = settings.I18N_LANG_DEFAULT
        # first try to parse a language code from header
        try:
            accept_code = parse_accept_lang(
                request.headers.get("accept-language", ""), I18N_LANG_OPTIONS,
            )
            if accept_code:
                self.code = accept_code
        except Exception:
            pass

        # then override this with any language code in URL
        for lang_option in I18N_LANG_OPTIONS:
            if request.url.path.startswith(f"/{lang_option}/"):
                self.prefix = f"/{lang_option}"
                self.code = lang_option
                break
        sentry_sdk.set_tag("locale", self.code)


class ContentNegotiation:
    """
    Choses a mimetype to return based on Accept header.

    Intended to be used for RESTful content negotiation from web endpoints to API.
    """

    def __init__(self, request: Request):
        self.mimetype = "text/html"
        if request.headers.get("accept", "").startswith("application/json"):
            self.mimetype = "application/json"


api = APIRouter()


@api.get("/", operation_id="get_home")
async def home() -> Any:
    return {"endpoints": {"/": "this", "/search": "fulltext search"}}

@api.head("/", include_in_schema=False)
async def root_head() -> Any:
    """
    HTTP HEAD only for the root path (and health check below). Requested by,
    eg, uptime monitoring tools. This is distinct from the CORS middleware (for
    OPTION).
    """
    return Response()

@api.get("/_health", operation_id="get_health")
async def health() -> Any:
    """
    Checks that connection back to elasticsearch index is working.
    """
    return Response()

@api.head("/_health", include_in_schema=False)
async def health_head() -> Any:
    return Response()

class HitsModel(BaseModel):
    count_returned: int
    count_found: int
    offset: int
    limit: int
    query_time_ms: int
    query_wall_time_ms: int
    results: List[ScholarDoc]


@api.get("/search", operation_id="get_search", response_model=HitsModel)
async def search(query: FulltextQuery = Depends(FulltextQuery)) -> FulltextHits:
    hits: Optional[FulltextHits] = None
    if query.q is None:
        raise HTTPException(status_code=400, detail="Expected a 'q' query parameter")
    try:
        hits = process_query(query)
    except ValueError as e:
        sentry_sdk.set_level("warning")
        sentry_sdk.capture_exception(e)
        raise HTTPException(status_code=400, detail=f"Query Error: {e}")
    except IOError as e:
        sentry_sdk.capture_exception(e)
        raise HTTPException(status_code=500, detail=f"Backend Error: {e}")

    # remove internal context from hit objects
    for doc in hits.results:
        doc.pop("_obj", None)

    return hits


web = APIRouter()


def locale_gettext(translations: Any) -> Any:
    def gt(s):  # noqa: ANN001,ANN201
        return translations.ugettext(s)

    return gt


def locale_ngettext(translations: Any) -> Any:
    def ngt(s, p, n):  # noqa: ANN001,ANN201
        return translations.ungettext(s, p, n)

    return ngt


def load_i18n_templates() -> Any:
    """
    This is a hack to work around lack of per-request translation
    (babel/gettext) locale switching in FastAPI and Starlette. Flask (and
    presumably others) get around this using global context (eg, in
    Flask-Babel).

    See related issues:

    - https://github.com/encode/starlette/issues/279
    - https://github.com/aio-libs/aiohttp-jinja2/issues/187
    """

    d = dict()
    for lang_opt in I18N_LANG_OPTIONS:
        translations = babel.support.Translations.load(
            dirname="fatcat_scholar/translations", locales=[lang_opt],
        )
        templates = Jinja2Templates(
            directory="fatcat_scholar/templates", extensions=["jinja2.ext.i18n"],
        )
        templates.env.install_gettext_translations(translations, newstyle=True)
        templates.env.install_gettext_callables(
            locale_gettext(translations), locale_ngettext(translations), newstyle=True,
        )
        # remove a lot of whitespace in HTML output with these configs
        templates.env.trim_blocks = True
        templates.env.lstrip_blocks = True
        # pass-through application settings to be available in templates
        templates.env.globals["settings"] = settings
        templates.env.globals["babel_numbers"] = babel.numbers
        d[lang_opt] = templates
    return d


i18n_templates = load_i18n_templates()


@web.get("/", include_in_schema=False)
async def web_home(
    request: Request,
    lang: LangPrefix = Depends(LangPrefix),
    content: ContentNegotiation = Depends(ContentNegotiation),
) -> Any:
    if content.mimetype == "application/json":
        return await home()
    return i18n_templates[lang.code].TemplateResponse(
        "home.html",
        {"request": request, "locale": lang.code, "lang_prefix": lang.prefix},
    )


@web.get("/about", include_in_schema=False)
async def web_about(request: Request, lang: LangPrefix = Depends(LangPrefix)) -> Any:
    return i18n_templates[lang.code].TemplateResponse(
        "about.html",
        {"request": request, "locale": lang.code, "lang_prefix": lang.prefix},
    )


@web.get("/help", include_in_schema=False)
async def web_help(request: Request, lang: LangPrefix = Depends(LangPrefix)) -> Any:
    return i18n_templates[lang.code].TemplateResponse(
        "help.html",
        {"request": request, "locale": lang.code, "lang_prefix": lang.prefix},
    )


@web.get("/search", include_in_schema=False)
async def web_search(
    request: Request,
    response: Response,
    query: FulltextQuery = Depends(FulltextQuery),
    lang: LangPrefix = Depends(LangPrefix),
    content: ContentNegotiation = Depends(ContentNegotiation),
) -> Any:

    if content.mimetype == "application/json":
        return await search(query)
    hits: Optional[FulltextHits] = None
    search_error: Optional[dict] = None
    status_code: int = 200
    if query.q is not None:
        try:
            hits = process_query(query)
        except ValueError as e:
            sentry_sdk.set_level("warning")
            sentry_sdk.capture_exception(e)
            search_error = dict(type="query", message=str(e))
            status_code = 400
        except IOError as e:
            sentry_sdk.capture_exception(e)
            search_error = dict(type="backend", message=str(e))
            status_code = 500

    headers = dict()
    if hits and hits.query_wall_time_ms:
        headers[
            "Server-Timing"
        ] = f'es_wall;desc="Search API Request";dur={hits.query_wall_time_ms}'
        if hits.query_time_ms:
            headers[
                "Server-Timing"
            ] += f', es;desc="Search Internal Time";dur={hits.query_time_ms}'
    return i18n_templates[lang.code].TemplateResponse(
        "search.html",
        {
            "request": request,
            "locale": lang.code,
            "lang_prefix": lang.prefix,
            "hits": hits,
            "search_error": search_error,
            "query": query,
        },
        headers=headers,
        status_code=status_code,
    )


app = FastAPI(
    title="Fatcat Scholar",
    description="Fulltext search interface for scholarly web content in the Fatcat catalog. An Internet Archive project.",
    version="0.2.0-dev",
    openapi_url="/api/openapi.json",
    redoc_url="/api/redoc",
    docs_url="/api/docs",
)

app.include_router(web)
for lang_option in I18N_LANG_OPTIONS:
    app.include_router(web, prefix=f"/{lang_option}")

# Becasue we are mounting 'api' after 'web', the web routes will take
# precedence. Requests get passed through the API handlers based on content
# negotiation. This is counter-intuitive here in the code, but does seem to
# work, and results in the OpenAPI docs looking correct.
app.include_router(api)

app.mount("/static", StaticFiles(directory="fatcat_scholar/static"), name="static")


@app.get("/favicon.ico", include_in_schema=False)
async def favicon() -> Any:
    return FileResponse(
        "fatcat_scholar/static/ia-favicon.ico", media_type="image/x-icon"
    )


ROBOTS_ALLOW = open("fatcat_scholar/static/robots.allow.txt", "r").read()
ROBOTS_DISALLOW = open("fatcat_scholar/static/robots.disallow.txt", "r").read()


@app.get("/robots.txt", include_in_schema=False)
async def robots_txt(response_class: Any = PlainTextResponse) -> Any:
    if settings.SCHOLAR_ENV == "prod":
        return PlainTextResponse(ROBOTS_ALLOW)
    else:
        return PlainTextResponse(ROBOTS_DISALLOW)


@app.exception_handler(StarletteHTTPException)
async def http_exception_handler(request: Request, exc: StarletteHTTPException) -> Any:
    """
    This is the generic handler for things like 404 errors.
    """
    # TODO: what if there is an error in any of the detection code?
    content = ContentNegotiation(request)

    if content.mimetype == "text/html":
        lang = LangPrefix(request)
        return i18n_templates[lang.code].TemplateResponse(
            "error.html",
            {
                "request": request,
                "locale": lang.code,
                "lang_prefix": lang.prefix,
                "error": exc,
            },
            status_code=exc.status_code,
        )
    else:
        resp: Dict[str, Any] = {"status_code": exc.status_code}
        if exc.detail:
            resp["detail"] = exc.detail
        return JSONResponse(status_code=exc.status_code, content=resp,)


# configure middleware

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=False,
    allow_methods=["GET"],
    allow_headers=[],  # some defaults always enabled
)

if settings.SENTRY_DSN:
    logger.info("Sentry integration enabled")
    sentry_sdk.init(
        dsn=settings.SENTRY_DSN,
        environment=settings.SCHOLAR_ENV,
        max_breadcrumbs=10,
        release=GIT_REVISION,
    )
    app.add_middleware(SentryAsgiMiddleware)

if settings.ENABLE_PROMETHEUS:
    app.add_middleware(PrometheusMiddleware)
    app.add_route("/prometheus/", metrics)